I01IE, 


«H^585W!WKS««W(8»«S«e^  ^;  nirii ,' 


GIFT  OF 


The  home  offers  us  a  variety  of  activities  which  help  in  the  best  development  of  body 

and  mind. 


CIVIC    SCIENCE 

IN  THE  HOME 


BY 
GEORGE  W.   HUNTER,  PH.D. 

PROFESSOR   OF   BIOLOGY,    KNOX  COLLEGE,   GALESBURG,    ILLINOIS 

FORMERLY  HEAD  OF  DEPARTMENT  OF  BIOLOGY,  DEWITT 

CLINTON    HIGH    SCHOOL,    NEW  YORK 

AND 

WALTER  G.  WHITMAN,  A.M. 

EDITOR,    GENERAL  SCIENCE   QUARTERLY 

PHYSICAL   SCIENCE   DEPARTMENT,   STATE   NORMAL   SCHOOL 
SALEM,   MASSACHUSETTS 


AMERICAN   BOOK  .COMPANY 

NEW  YORK  CINCINNATI  CHICAGO 

BOSTON  ATLANTA 


COPYRIGHT,  1921,  BY 

AMERICAN   BOOK  COMPANY 

A II  rights  reserved 

H.-W.      CIV.    SCI.   IN    HOME 

2  •!  !  w.  P.  i 


FOREWORD  TO  THE  TEACHER 

Man's  place  in  relation  to  science.  —  Living  things,  man  in- 
cluded, live  in  an  environment  which  is  made  up  of  certain 
definite  factors,  and  with  these  factors  living  things  react  and 
interact.  Some  of  these  factors  are  materials  —  things ;  other 
factors  are  forces.  The  ultimate  result  of  the  complex  we  call 
life  is  the  interaction  of  the  materials  and  forces  with  the  living 
things  on  the  earth.  Man,  however,  is  supreme  among  animals 
because  of  all  the  animals  he  alone  can  control  the  factors  of 
his  environment.  He  has  control  of  fire  and  water  and  elec- 
tricity. His  home  has  evolved  from  the  cave  of  primitive  man 
to  the  complex  housing  systems  of  the  present  age.  His  com- 
munal life  has  brought  with  it  new  problems  —  the  disposal  of 
wastes,  the  safeguarding  of  water  and  milk  supplies,  the  need 
of  community  sanitation  and  hygiene.  His  higher  civilization 
demands  use  of  machines,  the  need  of  which  his  forefathers 
neither  knew  nor  felt ;  of  transportation  and  communication ; 
of  more  varied  and  practical  education  as  well. 

Children's  interests  in  science.  —  In  the  midst  of  such  a  life 
as  this  our  children  are  growing  up.  Science  beckons  to  them 
from  every  side.  In  every  device  used  at  home  for  comfort 
and  better  living,  science  speaks.  The  telephone  and  telegraph, 
the  trolley  and  the  automobile,  the  airplane  and  submarine,  have 
all  become  part  and  parcel  of  their  daily  lives.  Many  of  the 
common  things  of  science  which  directly  affect  the  lives  of  chil- 
dren are  equally  interesting  to  both  sexes.  But  in  any  scheme 
of  modern  education  we  must  take  individual  differences  into 
consideration.  We  no  longer  educate  in  the  mass.  Sex,  age, 
environment,  capability,  heredity,  all  are  important  factors 
which  must  be  recognized  by  the  modern  teacher  as  having  a 
place  in  educational  practice  as  well  as  theory. 

459852 


6  FOREWORD  TO  THE  TEACHER 

The  project  method.  —  Since  we  must  allow  for  individual 
differences  in  our  scheme  of  education,  it  goes  without  saying 
that  mass  education,  which  does  not  account  the  child  as  a 
personality,  can  no  longer  be  admitted  as  a  part  of  our  scheme. 
We  must  take  cognizance  of  all  the  factors  mentioned  in  the 
last  paragraph ;  environment,  age,  and  sex  act  more  uniformly 
and  thus  may  be  taken  into  account  in  the  forming  of  classes 
or  groups.  But  individual  capability  and  endowments,  hered- 
ity's part  in  the  game  of  lif  e;  are  much  more  difficult  factors  with 
which  to  deal.  Recent  developments  in  educational  psychology 
show  that  one  method  of  attack,  however,  has  certain  elements 
which  may  be  used  successfully  with  any  group  of  children  not 
too  young  to  think  to  a  conclusion.  Problem  solving  of  one 
sort  or  another  is  common  to  all  the  activities  of  life.  It  is  the 
one  great  factor  which  goes  toward  making  for  success  or  failure 
in  life.  It  should  be  part  of  the  mental  attitude  of  every  edu- 
cated person.  Problem  or  project,  call  it  what  you  will,  repre- 
sents the  method  by  which  things  worth  while  in  life  are 
achieved.  It  offers  the  pupil  a  method  for  accomplishing  those 
things  in  life  which  mark  off  greatness  from  mediocrity  —  the 
leader  from  the  led. 

Methods  in  science  adapted  for  children.  —  We  hear  a  good 
deal  nowadays  about  the  logical  versus  the  psychological 
approach.  No  teacher,  and  the  word  is  used  in  its  truest  sense, 
can  teach  except  from  the  viewpoint  of  the  child.  Approached 
from  this  angle,  the  psychological  becomes  logical.  We  must 
have  a  plan,  but  we  must  remember  that  a  plan  may  sometimes 
be  changed  to  advantage.  Above  all  we  must  be  human.  If 
we  but  remember  how  we  looked  at  things  with  the  eyes  of 
thirteen  instead  of  those  of  forty-three  we  will  have  no  difficulty 
in  solving  the  method  of  lesson  attack.  We  must  remember, 
too,  that  concepts  grow  and  are  not  always  brought  to  ma- 
turity in  one  lesson.  The  cyclic  treatment  of  topics,  which  has 
been  followed  in  Civic  Science,  is  a  far  more  natural  method  of 


FOREWORD  TO  THE  TEACHER  7 

acquiring  information  than  a  dogmatic  statement,  made  per- 
haps with  proof  but  dimly  comprehended  and  soon  forgotten. 

The  textbook  in  introductory  science.  —  Any  book  in  intro- 
ductory science  should  be  based  on  the  facts  we  have  just  men- 
tioned. It  must  contain  an  adequate  amount  of  the  basic 
material  from  which  the  interpretation  of  the  common  things 
of  interest  in  life  may  be  gained,  and  it  must  also  be  adapted 
to  start  the  individual  boy  or  girl  whose  interest  has  been  awak- 
ened along  the  line  of  the  project  in  which  this  developing  in- 
terest would  naturally  flow.  Most  of  all  a  textbook  should 
interpret  to  the  child  the  part  played  by  the  various  natural 
factors  in  his  environment.  It  should  conceive  the  child  as 
the  center,  and  all  the  world  of  the  child  revolving  around  this 
center.  In  this  conception  boys  and  girls  would  first  become 
aware  of  the  vital  part  played  by  air,  water,  light,  heat,  and 
food  on  them  as  individuals  within  their  homes.  This  much  is 
common  to  all  —  the  application  of  certain  of  the  general  facts 
learned  could  then  be  carried  out  as  special  projects  by  various 
pupils  interested.  After  the  child  has  learned  the  meaning  of 
these  central  factors  in  the  home,  the  next  step  would  logically  be 
the  application  of  the  forces  of  nature  by  man  in  communal  life. 
In  short,  Civic  Science  plans  to  lead  the  child  in  a  manner  which 
is  both  logical  and  psychological  from  the  simple  factors  which 
make  up  his  environment  as  a  living  thing  to  the  complex  com- 
binations and  interactions  which  have  arisen  through  what  we 
call  civilization.  It  is  the  interpretation  of  this  complex  that 
Civic  Science  undertakes  with  the  belief  that  children,  if  given  a 
rational  point  of  view,  will  have  enough  varied  interests  to  build 
on  the  outline  which  follows.  They  will  thus  work  toward  the 
solution  of  those  things  in  science  which  seem  most  worth  while 
to  them  as  individuals  and  most  worthy  of  them  as  future 
citizens. 

Acknowledgments.  —  For  an  incentive  to  undertake  this 
work,  the  authors  are  indebted  to  those  educators  who  have 


8  FOREWORD  TO  THE  TEACHER 

written  much  on  the  subject  of  science  for  young  people,  par- 
ticularly, Thomas  M.  Balliet,  Thomas  H.  Briggs,  John  Dewey, 
Charles  W.  Eliot,  David  Snedden,  George  R.  Twiss,  and  John 
F.  Woodhull.  To  the  many  science  teachers  who  have  been 
active  in  developing  general  science  from  its  early  beginnings 
to  its  present  state,  the  authors  make  full  acknowledgment  for 
much  help  and  inspiration.  Acknowledgment  for  illustrative 
material  is  made  in  the  text.  The  drawings  were  nearly  all 
made  by  Mr.  F.  M.  Wheat,  of  the  George  Washington  High 
School,  New  York.  The  following  teachers  have  carefully  read 
the  entire  proof  and  made  many  valuable  suggestions :  Mr. 
M.  C.  Leonard,  Vice-principal,  Dickinson  High  School,  Jersey 
City ;  Miss  A.  P.  Hazen,  Head  of  the  Department  of  Biology, 
Eastern  District  High  School,  Brooklyn ;  and  Mr.  George  C. 
Wood,  Head  of  the  Department  of  Biology,  Commercial  High 
School,  Brooklyn ;  and  also  Miss  Lydia  Holtman,  Knox  Col- 
lege, Galesburg,  111. 

REFERENCE  BOOKS 

Dewey,  Hmv  We  Think,  especially  Chapters  IV,  V,  VI,  and  XV.     D.  C. 
Heath  Company. 

Flexner,  A  Modern  School,  New  York  Occasional  Papers  No.  3.     General 
Educational  Board,  New  York. 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Foreword.     American  Book 
Company. 

Huxley,  Physiography.     Appleton  Company. 

Snedden,  Problems  of  Secondary  Education,  Chapter  XXI,  Houghton  Mifflin 
Company. 

Trafton,  The  Teaching  of  Science  in  the  Elementary  School,  especially  Chap- 
ter V.     Houghton  Mifflin  Company. 

Twiss,  Science  Teaching,  especially  Chapters  II,  HI,  TV,  and  XIX.    The 
Macmillan  Company. 

Woodhull,  The  Teaching  of  Science,    The  Macmillan  Company. 


CONTENTS 

PAGE 

FOREWORD  TO  THE  TEACHER     .        .        .        .        .        .        .  5 

PART  I.    THE  HOME  AND   ITS  ENVIRONMENT 

CHAPTER 

I.    WHY  WE  STUDY  SCIENCE    .        .        .        .        .        .        .11 

II.    ESSENTIALS  or  AN  IDEAL  HOME 24 

III.  NATURAL  RESOURCES  OF  HOME  ENVIRONMENT  ...  39 

PART  II.     GOOD   HEALTH  IN  THE  HOME 

IV.  PURE  AIR -        •        .56 

V.    WATER  IN  THE  HOME  .        .        .        .        .                .        .  7-1 

VI.    THE  USES  OF  FOODS    .        .        .        .        .        .    ^._   ..1.  90 

VII.    PURE  FOOD  IN  THE  HOME  .        !".-,.        .       .       ...  115 

VIII.    HOUSEHOLD  PESTS  AND  How  TO  FIGHT  THEM  .        .        .  131 

IX.    How  WASTES  ARE  REMOVED  FROM  THE  HOME  .        .        .  144 

X.    GERM  DANGERS  AND  HEALTH  HABITS         .        .        .        .  158 

PART  III.    FEAT  IN  THE  HOME 

XI.    FUELS  AND  THF.IC  USES      .        .        .        .        ...  175 

XII.    HEATING  Our  HOMES.        .        .    v.        .     '  .        .        .  188 

XIII.  FIRE  PREVENTION  IN  THE  HOME 205 

XIV.  USES  OF  CLOTHING      ."  .'."'•.        .        .        .219 

PART  IV.    LIGHT  IN  THE  HOME 

XV.    SOURCES  OF  LIGHT  FOR  HOME  USE    .        *        .  <     .        .  238 

XVI.    IMPORTANCE  OF  OUR  EYES.        .        .     •  .        .        .        .  253 

PART  V.    THE  HOME  AND  ITS   SURROUNDINGS 

XVII.    MAKING  AND  BEAUTIFYING  THE  HOME       ...        .        •  267 

XVIII.     PLANNING  THE  HOME  GROUNDS  .        .       .       .,       .       .  286 

9 


io  /         CONTENTS 

CHAPTER  PAGE 

XIX.    THE  HOME  GARDEN 297 

XX.    PLANT  FRIENDS  AND  PLANT  PESTS 314 

PART  VI.    DEVICES   FOR  LABOR  SAVING  AND 
CONVENIENCE 

XXI.    SOME  SIMPLE  MACHINES  IN  THE  HOME      .        .        .        .331 
XXII.    How  ELECTRICITY  Is  USED  IN  THE  HOME         .        .        .    344 

XXIII.  How  ELECTRICITY  Is  CONTROLLED  IN  THE  HOME      .        .    359 

PART  VII.    RECREATION  IN  THE  HOME 

XXIV.  INDOOR  RECREATION 371 

XXV.    OUTDOOR  RECREATION .390 

INDEX  .        .        .       .   - 409 


PART    I.     THE    HOME   AND    ITS 
ENVIRONMENT 

CHAPTER  I 
WHY   WE   STUDY   SCIENCE 

Problems.  —  i.  Why  is  some  knowledge  of  science  essen- 
tial to  us? 

2.  Why  is  the  "  method  of  science  "  important? 

3.  What  is  a  science  project? 

Living  in  an  age  of  science.  —  Do  you  ever  stop  to  think 
you  are  living  at  a  time  when  science  has  done  more  to  make 
everyday  life  comfortable  than  at  any  other  time  in  the 
world's  history?  You  sleep  at  night  in  a  bed,  the  springs 
and  parts  of  which  were  made  by  machinery,  and  the  covers 
of  which  were  woven  by  a  complicated  process ;  you  wash 
with  soap  made  by  chemical  processes ;  you  eat  prepared 
breakfast  foods,  and  cook  on  a  gas,  coal,  or  wood  stove. 
You  eat  in  machine-pressed  dishes ;  ride  to  school  on 
electric  cars,  or  trains,  or  automobiles,  the  parts  of  which 
were  made  by  machines.  Every  part  of  your  waking  and 
sleeping  hours  you  come  in  contact  in  some  way  with  de- 
vices which  involve  a  knowledge  of  science,  and  yet  how 
few  actually  know  very  much  about  the  science  which 
underlies  all  these  useful  and  beneficial  inventions. 


12 


'.  /tyJtY:WE  STUDY  SCIENCE 


/M^';g:  ^ogress:  in  "science   recent.  —  Have  you   ever 
triougM  how  ma'riy'tKrrigs  have  come  into  common  use  since 

your  father  and  mother 
were  born?  X-rays, 
flash  lamps,  radium, 
the  pianola,  liquid  air, 
submarines,  gas  en- 
gines, sky  scrapers, 
harvesters,  vacuum 
brakes,  fireless  cookers, 
vacuum  bottles,  vacu- 
um cleaners,  street 
cars,  airplanes,  hydro- 
planes, motor  cycles, 
gas  mantles,  automo- 
biles, carpet  sweepers, 
asphalt  paving,  safety 
matches,  pneumatic  ap- 
pliances, moving  pic- 
tures, typewriters  and 
adding  machines,  wire- 
less telegraphy,  pneu- 
matic mailing  tubes, 
electric  heating  and 
cooking  apparatus,  tur- 
bines, paper  towels, 
electric  lighting,  reen- 
forced  concrete,  sani- 
tary drinking  fountains 
and  cups,  and  a  great 

A  triumph  of  modern  science.     How  many  scien-     many     Other      things 
tific  inventions  can  you  think  of  which  are  prob-          ,   .    . 
ably  utilized  in  this  large  office  building  ?  WnlCn  WC  JiaVC  COlTl&-tO 


SCIENCE  USED  IN  THE  DISCOVERY  OF  MALARIA  13 

look  upon  as  necessities  of  life.  Could  any  one  be  con- 
sidered educated  without  knowing  more  than  we  do  about 
science  ? 

Reasons  why  we  should  study  science.  —  Since  scien- 
tific devices  are  used  so  much  in  and  about  our  homes,  we 
ought  to  have  at  least  some  practical  knowledge  of  the 
common  things  in  science,  so  that  we  may  know  how  to 
help  solve  the  problems  that  come  to  us.  With  a  little 
knowledge,  we  can  fix  leaking  faucets;  we  can  find  out 
why  the  electric  bell  does  not  ring ;  we  can  explain  why 
the  ice  box  is  not  preserving  food  properly  or  why  the 
bread  does  not  rise.  Some  day  we  shall  be  called  upon  to 
earn  our  own  living.  Opportunities  for  promotion  in 
many  fields  of  work  will  be  small  for  those  who  do  not 
understand  common  things  in  science.  The  practical  ma- 
chinist who  can  apply  his  knowledge  of  the  principles  of 
science  to  the  working  of  his  machine  is  the  foreman  in 
the  shop.  Then  too,  our  health  depends  in  a  measure  upon 
the  knowledge  of  science.  It  used  to  be  thought  that 
diseases  like  diphtheria,  for  example,  were  the  dispensation 
of  Providence,  but  nowadays  we  look  nearer  for  the  cause, 
and  find  it  to  be  germs. 

An  example  of  how  the  method  of  science  was  used  in 
the  discovery  of  malaria.  —  The  Italians  thought  formerly 
that  malaria  was  caused  by  bad  air,  and  hence  they  called 
it  mat  aria.  The  discovery  of  malaria  is  an  interesting 
story.  It  was  near  the  end  of  the  last  century  that  a 
French  physician  named  Laveran  discovered  that  malaria 
was  probably  caused  by  a  tiny  parasite  which  lived  in 
the  blood  cells  of  man.  He  reasoned  that  this  was  so 
because  he  found  the  little  animal  only  in  the  blood  cells 
of  those  suffering  from  malaria.  A  little  later  an  English 


14  WHY  WE   STUDY   SCIENCE 

army  surgeon  named  Ross,  working  in  India,  found  after  a 
long  series  of  experiments,  that  mosquitoes  had  something 
to  do  with  malaria.  He  knew  that  they  were  blood-sucking 
insects,  and  that  they  were  always  present  where  malaria 


The  life  history  of  the  malarial  parasite.  This  cut  shows  parts  of  the  body  of  the 
mosquito  and  of  man.  The  mosquito  injects  the  crescent-shaped  bodies  into  the 
blood  of  man.  These  enter  the  blood  corpuscles,  develop  spores  which,  after  being 
released  from  the  corpuscle,  form  two  kinds  of  cells.  These  two  forms  of  the 
parasite  are  sucked  with  the  blood  into  the  body  of  the  mosquito,  where  the  other 
part  of  the  life  cycle  of  the  parasite  takes  place. 

was  frequent.  He  reasoned  that  mosquitoes  might  carry 
this  germ.  He  worked  a  long  period  of  time  before  he 
found  finally  that  a  certain  kind  of  mosquito,  called 
anopheles,  had  some  unusually  tiny  bodies  attached  to  the 


SCIENCE  USED  IN  THE  DISCOVERY  OF  MALARIA  15 


inside  of  their  stomachs.  These  little  microscopic  bodies 
were  full  of  black  specks.  Ross  found  later  that  these 
black  specks  were  only  present  after  a  mosquito  sucked 
blood  from  a  person  having  malaria.  By  a  process  of 
reasoning  and  experiments,  he  discovered  finally  that  not 
only  did  these  mosquitoes  carry  malaria,  but  that  people 
could  not  have  malaria  unless  they  were  bitten  by  one  of 
the  anopheles  mosquitoes,  for  a  malarial  parasite  has  to 
live  a  part  of  its  life  in  the  body  of  the  person  who  has 
malaria  and  another 
part  of  its  life  in 
the  body  of  the  mos- 
quito. 

Then  came  the 
testing  of  this  re- 
markable theory  in 
Italy.  A  number  of 
people  who  worked 


in  a  malarial  region, 
near  the  city  of 
Salerno,  were  per- 
suaded to  live  in 
houses  which  had 
been  carefully 
screened.  It  was 
discovered  that  the 
malarial  mosquito 
came  out  only  at 
night.  Practically  none  of  the  people  who  stayed  in  the 
house  at  night  behind  their  screens  got  malaria,  although 
almost  all  of  the  people  in  the  immediate  neighborhood 
were  suffering  from  the  disease. 


The  final  proof  that  the  mosquito  carries  malaria. 


16  WHY  WE   STUDY  SCIENCE 

The  final  proof  came  when  two  English  physician 
Dr.  Manson  and  Dr.  Warren,  allowed  themselves  to  1 
bitten  in  England  by  mosquitoes  which  had  been  sei 
from  Italy,  but  which  had  been  previously  fed  on  the  bloc 
of  a  person  having  malaria.  Neither  of  these  men  ha 
had  malaria  previously,  but  eighteen  days  after  they  we: 
bitten,  they  both  came  down  with  the  disease.  This 
an  excellent  example  of  how  scientific  method  is  applu 
in  the  discovery  of  new  facts  important  to  mankind.  A 
we  have  to  do  to  escape  malaria  is  to  be  sure  that  malari 
mosquitoes  do  not  bite  us. 

A  study  of  the  method  of  science.  —  If  we  study  th 
scientific  method  more  fully,  we  find,  first,  that  the  scientii 
has  a  reason  for  trying  to  solve  a  problem.  He  thinks  ov< 
this  problem,  and  finally  gets  clear  in  his  mind  just  wtu 
he  wants  to  find  out.  He  has  then  fixed  his  problem 
His  next  step  is  to  try  to  find  out  some  method  or  methoc 
of  solving  it.  This  he  does  by  thinking  over  various  waj 
in  which  he  can  attack  it.  He  finally  fixes  on  some  metho 
which  he  tries  out  by  means  of  experiments  to  test  wheth< 
his  theories  are  correct.  He  may  and  often  does  ha\ 
to  perform  hundreds  of  experiments  before  he  is  satisfie 
that  he  has  a  correct  solution.  This  was  the  case  with  D 
Ross  as  he  worked  over  his  problem  of  how  the  malarii 
mosquito  played  a  part  in  giving  the  disease  to  peopL 
At  length,  after  he  has  satisfied  himself  that  he  has  th 
solution  to  his  problem,  he  must  then  put  it  to  a  practice 
test.  This  was  done,  you  remember,  by  the  English  do< 
tors  who  allowed  themselves  to  be  bitten  by  the  mosquitoe: 
and  thus  proved  that  mosquitoes  transmit  malaria. 

The  method  of  science  useful  in  daily  life.  —  This  metho 
of  science  which  we  have  just  described  should  become 


SCIENCE  USED  IN  STRAIGHT  THINKING  17 

part  of  the  daily  life  of  every  educated  person.  It  should 
become  a  habit  of  mind,  a  way  of  thinking.  Scatter- 
brained people  may  think ;  we  find,  in  fact,  that  we  think 
when  we  daydream,  but  we  do  not  organize  our  thoughts, 
nor  do  we  put  them  to  any  use.  Science  was  once  called 
by  a  great  scientist,  "  organized  common  sense,"  and  such 
it  really  is.  Nowadays  too  many  people  reason  from  state- 
ments heard  which  they  want  to  be  true.  They  have 


We  estimate,  we  compare,  we  verify  in  the  method  of  science  and  in  everyday  life. 

heard  only  one  side,  and  do  not  care  to  know  any  other. 
Bolsheviki  are  good  examples  of  such  people.  People  who 
can  think  straight  are  the  ones  who  succeed  in  life.  A 
dangerous  attitude  of  mind  results  from  careless,  wrong 
modes  of  thinking. 

How  the  method  of  science  is  used  in  straight  thinking. 
—  When  we  think  properly,  we  are  using  some  steps  that 
the  scientist  uses  when  he  plans  to  work  out  his  problem. 
Take,  for  example,  any  question  in  your  daily  life  that  comes 
to  you.  It  comes  in  the  form  of  a  problem.  Your  father 
has  rented  a  new  house.  Your  mother  has  promised  you 
a  room  of  your  own,  and  a  new  rug  for  it..  You  are  visiting 
the  house.  You  look  at  the  room,  and  try  to  make  up  your 
mind  as  to  its  size.  You  think  it  is  about  ten  feet  by  twelve 

H.-WHIT.    CIV.   SCI.    IN   THE   HOME — 2 


i8  WHY  WE   STUDY  SCIENCE 

feet,  and  therefore  you  will  want  a  rug  not  larger  than 
eight  feet  by  ten  feet.  You  have  estimated  the  size,  but 
you  may  be  wrong.  You  compare  it  with  some  room  with 
which  you  are  familiar  in  your  own  house.  Yes,  it  seems 
to  be  about  ten  feet  by  twelve  feet  in  size,  but  you  decide 
it  will  be  better  to  measure  it.  So  you  get  a  tape  measure 
and  you  find  that  you  were  practically  correct.  You  have 
verified  your  conclusion.  In  other  words  you  have  followed 
the  method  of  scientific  thought.  You  have  estimated  the 
size,  compared  it  with  other  rooms,  and  reached  a  conclu- 
sion; you  measured  it,  and  found  you  were  correct. 

The  habit  of  scientific  thinking.  —  If  we  use  this  method 
at  all  times  we  shall  acquire  a  habit  of  mind  that  will  be  very 
useful  in  later  life.  This  method  teaches  us  to  be  accurate 
in  our  judgment.  It  teaches  us  to  observe.  It  teaches 
us  not  to  accept  a  statement  without  evidence.  It  teaches 
us  to  weigh  the  evidence,  then  draw  our  conclusions  and 
finally  to  verify  our  conclusions.  This  habit  of  mind  is 
worth  much  more  than  any  number  of  facts  that  this  book 
can  give. 

How  we  use  this  method  in  our  home  work.  —  We  get 
out  of  life  just  about  what  we  put  into  it.  Each  one  of  us 
will  get  just  as  much  from  the  method  of  science  in  this 
course  as  we  are  willing  to  work  out  with  enthusiasm. 
In  any  event,  boys  and  girls  taking  a  course  in  general  sci- 
ence will  get  a  great  deal  of  valuable  information  which 
will  be  useful  during  life.  Much  of  the  information  will 
be  found  in  this  book  and  in  other  books  which  are  suggested 
in  the  reference  lists.  But  the  method  of  doing  things  we 
must  learn  outside  the  reading  books.  To  work  out  home 
problems  or  projects  with  such  simple  apparatus  as  is 
needed  to  draw  conclusions,  is  far  more  profitable  than 


THE  PROJECT  19 

memorizing  any  number  of  facts,  for  by  scientific  methods 
such  as  these,  people  make  discoveries  which  are  of  value 
to  the  world. 

The  project  and  how  it  may  be  worked  out.  —  You  are 
the  one  to  plan  your  own  project  and  work  out  the  prob- 
lems connected  with  it.  It  will  not  mean  so  much  to  you 
unless  you  want  to  know  about  the  thing  you  are  trying  to 
do.  Books,  people,  and  experiments  may  all  help  toward 
the  achievement  of  your  project,  but  you  must  carry  it 
through  yourself.  Take,  for  example,  a  project  to  deter- 
mine the  best  methods  of  cleaning  a  room.  This  would 
mean  investigation  on  your  part  of  the  construction  of 
brooms,  wet  and  dry  dust  cloths,  dustless  dusters,  carpet 
sweepers,  vacuum  cleaners,  and  of  the  methods  used  in  per- 
forming the  work.  Not  only  should  the  mechanical  work- 
ing of  these  devices  be  understood,  but  also  the  amount  of 
time  and  labor  spent  in  cleaning  a  room  with  each  must 
be  estimated  or  measured  separately.  We  would  naturally 
be  interested  to  know  also  how  much  this  time  is  worth, 
and  that  should  go  into  our  estimate  of  the  value  of  the 
different  methods.  But  more  important  is  the  knowledge 
of  how  much  dust  is  raised  by  each  method  and  the 
relative  number  of  bacteria  which  would  be  stirred  about 
in  the  air.  To  understand  this  it  would  be  necessary  for 
us  not  only  to  know  something  about  the  bacteria  them- 
selves, but  also  to  perform  experiments  with  a  series  of 
prepared  culture  dishes  by  which  we  would  determine  the 
relative  number  of  bacteria  in  the  air  during  each  method 
of  cleaning.  These  culture  dishes  may  be  obtained  from 
the  board  of  health,  or  a  good  laboratory,  or  a  culture 
medium  made  and  the  dishes  filled  and  sterilized  in  the 
school  laboratory.  Eventually  you  have  a  series  of  facts 


20  WHY  WE   STUDY  SCIENCE 

which  enable  you  to  determine  which  is  the  best  method 
of  cleaning  a  room.  A  written  report  giving  all  data  by 
which  you  have  reached  your  conclusions  and  including 
interesting  facts  learned  by  your  study  completes  your 
project. 

In  order  that  you  may  be  able  to  choose  some  one  project 
in  which  you  will  be  interested,  a  suggested  list  of  projects 
follows  at  this  time.  These  projects  will  be  mentioned 
again  in  connection  with  the  chapters  with  which  they  are 
connected.  But  since  projects  require  planning  and  often 
a  considerable  length  of  time  to  work  out,  you  should  choose 
your  projects  now  and  begin  to  plan  work  on  them  at  once. 
In  this  way  you  will  be  ready  to  report  to  the  class  at  the 
right  time. 

A  LIST  OF  SUGGESTED   PROJECTS 

1.  To  learn  the  advantages  of  renting  and  of  owning  one's  home.    Page  24. 

2.  To  make  a  home  laboratory.     Page  39. 

3.  To  discover  and  remedy  harmful  effects  of  air  about  the  home.     Page  39. 

4.  To  increase  my  lung  capacity.     Page  56. 

5.  To  secure  pure  air  in  my  bedroom.     Page  57. 

6.  To  prepare  for  life  saving  where  artificial  respiration  must  be  used. 

Page  57. 

7.  To  make  a  lift  pump.     Page  74. 

8.  To  see  how  much  water  is  wasted  by  dripping  faucets.     Page  74. 

9.  To  see  what  nutrients  are  in  the  foods  commonly  used  in  my  home. 

Page  90. 

10.  To  obtain  starch  from  potatoes.     Page  90. 

11.  To  plan  for  economical  buying  for  our  family  for  one  week.     Page  91. 

12.  To  test  and  preserve  eggs  for  home  use.     Page  115. 

13.  To  pasteurize  the  home  milk  supply.     Page  116. 

14.  To  exterminate  flies  from  my  home.     Page  131. 

15.  To  prepare  myself  to  keep  the  house  plumbing  in  order.     Page  144. 

16.  To  compare  my  daily  use  of  time  with  an  ideal  plan.    Page  158. 

17.  To  form  correct  health  habits.     Page  159. 

18.  To  make  a  house  thermometer.     Page  175. 

19.  To  qualify  as  an  expert  heating  device  operator  in  my  home.    Page  188. 


TOOLS  WITH  WHICH  WE  WILL  WORK  21 

20.  To  learn  how  my  coal  range  is  constructed  and  how  to  run  it.     Page  189. 

21.  To  remove  the  fire  hazards  from  my  home.     Page  205. 

22.  To  find  out  what  my  clothes  are  made  of.     Page  219. 

23.  To  improve  the  lighting  in  my  home.     Page  238. 

24.  To  remedy  any  eye  defects  I  may  have.     Page  253. 

25.  To  plan  an  ideal  house.     Page  267. 

26.  To  become  a  landscape  gardener  for  my  own  home.     Page  286. 

27.  To  learn  the  soil  needs  in  my  garden  for  any  particular  crop.     Page  297. 

28.  To  eliminate  the  plant  pests  from  my  home  grounds.     Page  314. 

29.  To  keep  the  machines  of  the  home  in  good  working  condition.  Page  33 1 . 

30.  To  install  an  electric  bell  in  my  home.     Page  344. 

31.  To  install  a  night  light  in  my  bedroom.     Page  359. 

32.  To  understand  the  mechanism  of  the  piano  and  the  piano  player.     Page 

37i- 

33.  To  plan  how  to  utilize  the  playgrounds  of  the  home  lot.     Page  390. 

Tools  with  which  we  will  work. — A  notebook  in  which  to 
make  careful  notes  of  all  work  done  is  an  essential  part  of 
our  equipment.  We  should  always  take  notes  of  every- 
thing we  do,  both  in  the  laboratory  and  at  home.  These 
notes  should  be  carefully  kept,  and  drawings  made  to  illus- 
trate them,  either  with  a  hard  pencil  or  with  a  drawing  pen. 
We  must  learn  to  use  instruments  with  which  to  measure. 
The  use  of  the  metric  system  is  best  for  all  scientific  meas- 
urements, and  a  knowledge  of  the  metric  tables  will  be 
found  valuable.  We  must  also  know  how  to  use  a  com- 
pass and  a  T-square,  and  other  instruments  useful  in  diagram 
making.  Perhaps  the  most  essential  thing  of  all  is  to  learn 
the  value  of  accurate  figures,  as  this  is  needful  in  the  mak- 
ing and  understanding  of  graphs.  A  graph  is  the  diagram- 
matic representation  of  a  certain  number  of  figures.  An 
example  is  seen  in  the  diagram  on  page  22,  in  which  we  are 
illustrating  the  changes  of  temperature  which  take  place 
during  a  day.  The  figures  of  the  thermometers  and  clock 
faces  show  the  temperatures  at  different  times  durin^-the 
day  and  the  hours.  The  figure  on  the  squared  paper  shows 


22  WHY  WE  STUDY  SCIENCE 

how  the  graph  is  constructed.  It  is  important  to  learn 
the  making  and  understanding  of  simple  graphs,  as  a 
knowledge  of  this  kind  should  be  part  of  the  equipment 


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of  every  well-informed  boy  and  girl  to-day.  Last  of 
all,  and  perhaps  most  important,  we  need  enthusiasm  for 
our 'work.  Success  along  any  line  requires  attention, 
thought,  and  interest.  Interest  is  valuable  in  school  work 


REFERENCE  BOOKS  23 

and  failure  is  often  due  to  indifference.  Surely  in  this 
great  world  of  science  about  us,  there  is  enough  to  interest 
each  one  of  us. 

REFERENCE   BOOKS 

Fall,  Science  for  Beginners,  Chapters  I  and  II.     World  Book  Company. 

Hunter,  A  Civic  Biology,  Chapter  I.     American  Book  Company. 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapter  I.     American  Book  Company. 

Lee,  Health  and  Disease  (Advanced),  Chapter  XV.     Little,  Brown,  and  Company. 

Ritchie,  A  Primer  of  Sanitation,  Chapter  XXIV.     World  Book  Company. 

Smith  and  Jewett,  Introduction  to  the  Study  of  Science,  Chapter  XII.     The  Mac- 

millan  Company. 
Winslow,  Healthy  Living,  Chapter  XXIII.     Merrill  Company. 


CHAPTER  II 

THE   ESSENTIALS   OF  AN   IDEAL  HOME 

Problems.  —  i.  To  see  how  marts  idea  of  home  has 
changed  since  remote  ages. 

2.  To  see  what  our  present  homes  do  for  us. 

3.  To  learn  how  to  secure  efficiency  in  the  home. 

4.  To  see  what  a  home  can  contribute  to  our  health. 

Home  Laboratory  Exercise.  —  To  make  out  a  score  card  for  my  own 
home. 

Project  I.  —  RELATIVE  ADVANTAGE  OF  RENTING  AND  OF  BUILD- 
ING ONE'S  HOUSE. 

If  your  parents  are  renting  a  house  or  apartment,  you  may  be 
interested  to  undertake  this  project. 

1.  Selection  of  a  desirable  home  site.    Look-  over  the  vacant 
lots  available  for  building  in  various  sections  of  the  town  or  city. 
Value  of  lot  ?    Why  selected  ? 

2.  From  study  of  magazines   (consult  library)  select  suitable 
house  plans.     Probable  cost  ?     Other  expenses  to  equip  the  house  ? 

3.  How  could  this  house  be  built  ?    Mortgage.    Building  loans. 
Cost  of  hired  money.     How  much  must  the  owner  invest  ? 

4.  Compare  yearly  cost  of  living  in  one's  own  house  and  in  rentals. 

What  is  a  home  ?  —  To  the  boy  or  girl  who  reads  this, 
home  is  the  place  where  he  or  she  slept  last  night,  arose 
this  morning  to  an  early  breakfast,  and  then  left  bright 
and  early  so  as  to  be  in  time  for  school.  A  boy  probably 
thinks  of  the  closet  in  his  bedroom,  filled  with  his  books 

24 


HOW  HOMES  HAVE   CHANGED  25 

and  games,  his  skates  and  gun.  The  girl  thinks  of  her 
dainty  bedroom,  with  its  pretty  pictures  and  hangings, 
and  both  probably  think  more  than  anything  else  of 
the  father  and  mother  who  make  life  really  worth  while 
at  home.  Home,  then,  is  more  than  a  place  to  live  in ;  it 
means  father,  mother,  brothers,  and  sisters ;  it  means 


A  suburban  home. 


family  life,  with  all  its  give  and  take,  its  unselfishness  and 
loyalty  to  the  ideals  which  father  and  mother  believe  to  be 
right. 

How  homes  have  changed  from  their  first  beginnings  on 
the  earth.  —  There  was  a  time  a  good  many  thousand 
years  ago  when  people  living  on  the  earth  had  no  real 
homes.  They  were  nomads,  traveling  from  one  place  to 
another,  staying  here  a  night  and  there  a  day,  never  remain- 
ing long  in  one  place.  Then  came  the  discovery  of  fire. 


26 


THE   ESSENTIALS   OF  AN   IDEAL  HOME 


With  the  fire  they  warmed  the  caves  ;  and  in  consequence 
people  lived  in  greater  comfort  and  made  these  caves  the 
first  real  homes.  Then  they  began  to  domesticate  or  tame 
the  wild  horses  and  wilder  cattle  with  which  they  came  in 
contact  and  to  discover  that  certain  fields  of  wild  grasses 

were  good  fodder 
for  their  horses  and 
cattle.  Later  these 
wild  grasses  were 
cultivated  and  the 
first  cereal  crops 
came  into  existence 
for  man.  Man  be- 
gan to  build  perma- 
nent homes  now,  be- 
cause he  had  food 
to  eat  and  fire  with 
which  to  cook. 
Probably  the  first  of 
these  homes  were 
nothing  but  tents 
made  of  skins,  or 
rude  huts,  but  they 
were  enough  for  the 
few  needs  of  primitive  men  and  women.  Food  and  cattle 
were  more  abundant  in  certain  places,  where  water  and 
wood  for  fire  were  plentiful.  These  advantages  attracted 
a  number  of  people  who  came  to  live  near  each  other. 
Mutual  protection  was  gained  also,  and  so  we  have  the 
beginnings  of  a  town  or  community.  It  is  a  long  and  far 
cry  from  the  tiny  collection  of  huts  to  the  modern  great 
city,  but  our  cities  and  towns  of  to-day  have  grown  from 


Indian  tepee.     A  type  of  very  primitive  home. 


THE  IDEAL  HOME  SITE 


27 


just  such  beginnings  as  we  have  been  talking  about  in 
this  paragraph. 

What  home  life  does  for  us.  —  Doubtless  each  one  of  us 
thinks  of  his  home  as  a  place  for  shelter,  for  food,  for 
material  comforts  of  all  kinds,  but  it  should  be  more  than 
this.  The  home  should  be  the  center  of  a  little  group  in 
which  absolute  loyalty  is  seen  instead  of  selfishness  and  in- 
dividual rights.  At  the  present  time  this  country  of  ours 
suffers  much  because  of  the  lack  of  team  work  on  the  part 
of  all  men  and  women  who  share  its  benefits.  Real  home 
life  should  teach  us  cooperation  and  unselfishness,  not 
individualism  and  selfishness. 

The  home  requirements  of  civilized  man.  —  Man,  if 
he  is  to  be  a  healthy  individual,  and  if  he  wishes  to  remain 
so,  should  have  the  following : 

1.  Pure  air  —  this  means  air  free  from  dust  and  germs, 
smoke  and  bad  odors. 

2.  Pure  water  —  water  free  from  all  dirt  and  germs. 

3.  Good  and  plentiful  food,  well  taken  care  of  and  prop- 
erly cooked. 

4.  Moderate  heat,  both  in  summer  and  in  winter. 

5.  Plentiful  light,  both  natural  and  artificial. 

6.  Clothing  suitable  to  the  time  of  year. 

7.  A  home  well  planned,  well  ventilated,  well  lighted, 
with  some  ground  around  it  for  a  garden  and  playground. 
If  the  latter  is  not  possible,  playgrounds  and  parks  should 
be  provided  in  the  near  vicinity. 

The  ideal  home  site.  —  We  have  already  spoken  of  the 
detached  house  being  the  ideal  place  in  which  to  live.  This 
is  not  only  because  of  the  air  space  around  it  on  all  sides, 
making  it  cooler  in  summer  and  giving  good  ventilation, 
but  also  because  of  the  privacy  which  comes  from  living 


28 


TIIK    I'SSKNTIALS   OF   AN    IDKAL   TTOME 


in  ;i  house  separated  from  its  neighbors,  I  )rt;i<  lied  house's 
;irc  more  frequently  owned  by  those  who  live  in  them,  ;ind 
this  helps  to  make  the  owner  more  thrifty.  One  is  always 
more  «, -i rel'iil  of  a  house  he  owns  than  of  one  he  rents. 
Thru,  too,  the  garden  is  indire<lly  a  sourer  of  profit  as 
well  as  of  health  and  pleasure.  Many  families  furnish  all 


The  house  in  the  diagram  IB  ideally  located  as  regards  drainage.  The  irregular  lines 
are  contour  lines,  each  representing  5  feet  in  altitude.  Make  a  diagram  in  your 
notebook  showing  a  cross  section  through  house  and  grounds,  indicating  differ- 
ences in  elevation. 

the  vegetables  nrrdrd   during   the  summer  from  a  small 
garden,  carefully  planned  and  tended. 

If  we  live  in  the  city,  both  light  and  air  are  very  im- 
portant factors  for  our  consideration.  In  most  cities 
nowadays,  good  laws  have  been  made  which  require  wide 
air  shafts  and  sufficient  window  space  in  all  apartments 
or  dwellings.  But  in  many  cities  in  the  United  States, 
we  still  see  houses  like  the  one  shown  in  the  picture,  m  a 


THE  IDEAL  HOME  SITE 


29 


A  congested  district. 


Compare  this  detached  house  with  the  houses  shown  in  the  picture  above.    In  which 
place  would  you  rather  live  ? 


THE   ESSENTIALS   OF  AN  IDEAL  HOME 


congested  district,  where  neither  light  nor  air  is  abundant 

enough  for  healthy  living. 

Some  ways  to  work  for  an  ideal  home.  —  No  doubt 

we  would  all  like  to  live  in  a  home  that  is  ideal.     While 

this  is  not  possible, 
for  no  one  of  us  is 
perfect,  yet  we  can 
do  a  great  deal  to 
better  the  condi- 
tions under  which 
we  live.  The  fol- 
lowing paragraphs 
will  tell  us  some  of 
the  ways  in  which 
we  may  improve 
our  homes. 

Crowding  a  men- 
ace to  health.  - 
Although  it  is  not 
always  easy  for  us 
to  change  the  place 
where  we  live,  yet 
when  we  realize 
that  crowding  in  a 
big  city  frequently 

This  map  shows  how  cases  of  tuberculosis  recur  in  the  matp«;  a        hip"hpr 
same  houses  year  after  year.    Each  black  dot  repre-  UlgUC 

sents  one  case  of  tuberculosis.     The  region  is  one  of  rl^a+Vi  ratA        -or  A 

the  most  densely  populated  regions  in  New  York.  UCdLll  idLC, 

should  be  willing  to 

plan  for  a  better  place  in  which  to  live.  The  map  shown 
in  the  illustration  gives  ample  proof  that  some  crowded 
conditions  help  to  cause  diseases.  All  of  the  little  dots  in 
the  picture  represent  cases  of  tuberculosis.  Notice  how 


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CARELESSNESS  31 

numerous  the  cases  are  in  certain  houses.  This  may  mean 
that  under  the  crowded  conditions  in  which  people  lived, 
the  disease  was  more  easily  transmitted  from  one  person 
to  another.  A  small  one-family  house,  if  one  can  afford 
it,  is  far  better  than  the  crowded  apartment  or  tenement. 

Cleanliness  a  factor  in  the  home.  —  A  large,  airy  house 
in  a  good  location  is  not  the  only  necessity  for  good  health. 
If  houses  are  kept  closed  long,  or  allowed  to  run  down ;  if 
they  have  leaky  gas  or  sewage  pipes,  or  if  they  are  over- 
run with  rats  or  infested  with  flies,  they  are  far  from  being 
sanitary  and  healthful.  A  clean  fly  may  have  twenty  thou- 
sand germs  tucked  away  on  its  legs  or  body,  while  a  dirty 
one  may  carry  several  million.  We  can  at  least  keep  our 
homes  clean  and  free  from  dirt,  and  we  can  also  be  clean 
in  our  own  person  and  clothes. 

Carelessness.  —  Carelessness  always  plays  a  big  part 
in  making  our  homes  unpleasant  places  in  which  to  live. 
There  are  numerous  calamities  besides  sickness  which  may 
come  to  the  home.  One  of  the  most  treacherous  is  fire.  The 
fires  in  the  United  States  average  1500  a  day.  The  cause 
of  a  great  many  of  these  is  a  carelessly  dropped  match, 
a  lighted  cigarette,  the  gas  turned  on  and  forgotten,  or  the 
electric  iron  thoughtlessly  left, — in  other  words,  carelessness. 

What  is  more  valuable  than  a  pair  of  good  eyes?  Close 
your  eyes  for  five  minutes,  and  think  what  life  would 
be  if,  instead  of  five  minutes,  it  was  for  five  years,  or  for 
your  whole  life  that  you  were  to  be  surrounded  by  dark- 
ness. Think  of  what  you  would  miss  in  life.  Carelessness 
in  caring  for  eye  defects,  such  as  nearsightedness  or  far- 
sightedness, or  careless  use  of  lights  and  lighting,  —  all  of 
these  things  may  mean  a  lessened  use  later  in  life,  or  per- 
haps loss  of  use  of  these  important  organs. 


32  THE   ESSENTIALS   OF  AN   IDEAL   HOME 

Efficiency  in  the  home.  —  Nowadays  we  frequently  hear 
the  word  "  efficiency."     We  have  efficiency  engineers  in 


Thomas  Edison,  one  of  our  greatest  inventors. 

great  manufacturing  plants  to  see  that  the  most  is  made  of 
the  machinery,  and  the  time  of  the  workmen.  Why  should 
not  each  one  of  us  be  an  efficiency  engineer  in  our  own 
home?  We  should  all  train  ourselves  to  discover  where 
there  is  wasted  energy,  and  then  study  how  to  prevent  it. 
In  factories  machines  have  largely  replaced  hand  labor. 
The  machines  last  only  a  few  years,  and  are  then  replaced 
by  others  which  can  do  the  work  better.  Why  not  apply 
this  business  principle  of  efficiency  to  our  homes  ?  It  would 
mean  more  time  for  recreation,  reading,  and  social  life. 
The  reduction  of  house  work  and  the  use  of  sanitary  con- 
veniences would  often  do  much  to  make  the  health  of  the 


RECREATION  IN  THE  HOME 


33 


family  better.  How  is  it  in  your  home?  Could  a  few 
dollars  be  well  spent  for  equipment  which  would  make 
mother's  life  easier?  Why  not  study  the  situation  as 
a  home  project? 

The  habit  of  work.  —  The  great  inventor,  Edison,  in 
his  seventies,  is  able  now  to  work  long  hours  day  after  day. 
It  was  his  habit  to  work,  even  when  he  was  a  small  boy. 
We  find  that  most  men  and  women  who  have  developed 
into  leaders  accustomed  themselves  to  work  when  they 
were  young.  Learn  to  accept  your  share  of  the  home 


123  4 

Practice  these  exercises  every  morning  and  evening  and  watch  the  effect  upon  your 
general  development.     (After  Tolman.) 

duties,  for  thus  you  will  develop  a  sense  of  responsibility 
and  habits  of  industry.  Learn  to  do  home  tasks  willingly, 
for  thus  you  will  develop  unselfishness.  The  efficiency  of 
a  household  is  lowered  by  every  idle  member  who  lives 
there.  Learn  now  to  be  a  helper,  and  some  day  you  will 
assume  more  easily  the  responsibilities  which  will  come  to 
you  when  you  are  grown  up. 

Recreation  in  the  home.  —  It  is  an  old  saying  that  all 
work  and  no  play  makes  Jack  a  dull  boy.  All  work  is 
wrong,  and  all  play  is  wrong,  but  play  is  just  as  important 
as  work  for  normal  boys  and  girls.  Recreation  sometimes 
means  re-creation,  for  we  are  really  made  over  by  doing 

H.-WHIT.    CIV.   SCI.    IN  THE   HOME  —  3 


34 


THE   ESSENTIALS   OF  AN  IDEAL  HOME 


interesting  things  which  rest  our  body  and  mind.  Reading, 
music,  visiting  our  friends,  playing  games,  are  all  good 
types  of  indoor  recreation  and  outdoor  exercise  and  are 
absolutely  necessary  for  a  growing  boy  and  girl.  Our  lungs 
need  developing,  as  do  our  muscles.  Baseball,  tennis,  walk- 
ing, hiking,  canoeing,  camp- 
ing —  all  of  these  have  their 
place,  and  even  if  we  have 
no  opportunity  for  these,  a 
little  yard  space  is  sufficient 
for  such  games  as  tether- 
ball,  Russian  nine-pins,  vol- 
ley ball,  or  hand  ball. 

You  must  obey  health 
rules.  —  Most  of  all,  daily 
following  the  rules  of  good 
health  will  do  more  than 
anything  else  to  make  your 
life  a  happy  and  a  helpful 
one.  Did  you  ever  think 
what  it  would  mean  not  to 
be  able  to  run  a  foot  race,  or 
make  a  high  jump,  or  play  a 
game  of  tennis  or  baseball  ?  Without  proper  attention  to 
the  rules  of  right  living,  proper  eating,  drinking,  breathing, 
and  care  of  your  bodily  organs,  even  the  strongest  of  you 
may  become  weak.  You  may  be  in  the  best  of  health  now, 
but  if  you  are  not  willing  to  continue  the  proper  care  of 
your  body,  you  may  pay  the  cost  later.  Do  not  try  to  cheat 
somebody  else  by  not  brushing  your  teeth  to-day,  or  not 
wearing  the  warm  clothes  that  mother  suggested,  or  by 
reading  too  long  in  that  poor  light,  for  the  only  one  you 


This  boy,  as  a  result  of  exercise,  fresh 
air,  and  nourishing  food,  has  a  strong 
healthy  body.  He  is  able  to  take  care 
of  himself.  (After  Davison.) 


SCORING  THE  HOME  35 

are  cheating  is  yourself.  Be  faithful  in  your  health  habits ; 
it  pays  in  the  long  run. 

Scoring  the  home.  —  Emerson  has  said  that  we  must 
"hitch  our  wagon  to  a  star."  This  really  means  that  we 
must  have  high  ideals  in  life.  In  order  to  estimate  your  own 
homes  in  the  light  of  the  chapter  you  are  now  reading,  there 
follows  a  score  card  which  each  boy  and  girl  should  study, 
and  then  for  his  or  her  own  satisfaction  attempt  to 
score  his  or  her  own  home.  Remember  to  be  honest  in 
your  scoring,  and  although  your  score  may  seem  low, 
nobody's  score  will  be  perfect,  because  we  have  "  hitched 
our  wagon  to  a  star."  This  home  project  will  be  a  pre- 
liminary survey  of  our  homes,  and  in  a  later  chapter,  we 
shall  make  a  more  careful  study  under  each  of  the  head- 
ings in  this  score  card.  You  will  notice  that  this  first 
score  card  has  three  columns  headed  respectively,  "  Per- 
fect score,"  "  My  first  (guess)  score  "  and  "  My  final  (real) 
score."  This  means  that  you  are  to  make  an  outline  of 
this  score  card  as  a  preliminary  exercise  for  your  note- 
book. In  the  second  column  place  the  score  you  think 
you  ought  to  have,  after  having  first  consulted  the  score 
cards  you  are  referred  to  at  the  ends  of  certain  of  the  chap- 
ters. The  scores  should  be  totaled  and  a  grand  total  ob- 
tained. The  third  column  marked  "  My  final  (real)  score  " 
will  be  filled  little  by  little  as  you  study  the  future  chapters. 
You  will  probably  find  that  your  first  estimate  was  far  too 
high  and  thus  the  third  column  will  serve  to  check  up 
on  your  "  guess  "  or  first  estimate.  This  shows  a  use  of 
the  scientific  method  referred  to  in  the  first  chapter,  and 
will  be  excellent  practice  for  you. 

The  score  card  that  is  given  is  only  a  suggestion  and 
may  be  advantageously  changed  to  meet  local  conditions. 


THE   ESSENTIALS   OF  AN   IDEAL   HOME 


HOME   SCORE   CARD 


PERFECT 

SCORE 


MY  FIRST 

(GUESS) 

SCORE 


MY  FINAL 

(REAL) 
SCORE 


ENVIRONMENT 

Pure  air 

Pure  water 

Well-drained  soil 

Plenty  of  sunlight 

Not  too  great  extremes  of  heat  or  cold 
Foods  supplied  from  home  garden  .     . 
Foods  cheap  and  good       


WATER  IN  MY  HOME 

Safe  supply 

Ample  supply  .... 
All  parts  or  home  supplied 
Good  condition  plumbing 
Soft  water  provided  .  .  . 


3.    FOODS  m  MY  HOME 

A  well-balanced  diet 

Right  diet  for  occupation  and  environment 

Foods  easily  digestible 

Foods  economical 

Foods  properly  prepared  and  cooked  .     . 


4.  CARE  OF  FOODS  IN  MY  HOME 

Clean  kitchen  and  utensils 10 

Good  refrigeration 10 

Sterilization  and  pasteurization 10 

Proper  use  of  preservatives 10 

Protection  from  insects,  etc 10 

5.  HOUSEHOLD  PESTS 

No  flies       10 

No  mosquitoes     . 10 

No  body  pests  (fleas,  bedbugs,  head  lice)  .  10 
No  food  or  cloth  pests  (roaches,  ants,  wee- 
vils, clothes  moths,  etc.) 10 

No  rats  or  mice 10 

6.  REMOVAL  OF  WASTES 

Exposed  plumbing 10 

All  porcelain  fixtures 10 

Have  a  working  knowledge  of  system  .    .     :  10 

Sewer  connections  or  septic  tank     ....  10 

Garbage  pail  pr<||>erly  kept 10 

7.  PERSONAL  HEALTH  HABITS 

(See  page  173) 100 

PROTECTION  AGAINST  DISEASE 

(See  page  174) 50 

8.  FUELS 

Warmth  obtained 10 

Ventilation  and  protection  against  loss  of 

heat 10 

Economy  of  fuel  10 

Economy  in  time  and  work  in  attending  to 

heating  plant 10 

Efficiency  of  cooking  stove  ......  10 

9.  CLOTHING,  BATHING,  AND  VENTILATION 

Proper  outer  clothing 10 

Proper  and  clean  underclothing      ....  10 

Bathing 10 


SCORING  THE  HOME 

HOME    SCORE    CARD  —  Continued 


37 


PERFECT 
SCORE 

MY  FIRST 
(GUESS) 
SCORE 

MY  FINAL 
(REAL) 
SCORE 

g.    CLOTHING,  ETC.  —  Continued 
Proper  bedroom  hygiene    . 
Proper  home  ventilation    

10 
10 

10.    LIGHTING  MY  HOME 
Sunlight  plentiful      

10 

\Yindows  ample,  wall  papers  good  reflectors 
Artificial  lighting  economical      
Proper  lighting  for  all  kinds  of  work  .     .     . 
Good  systems  of  lighting  used    

10 
10 
10 
10 

ii.    PROPER  CARE  OF  MY  EYES 
See  Chapter  XVI,  Page  266,  for  items     .     . 

So 

12.    MY  HOUSE 
Detached  house        

IO 

IO 

Bedrooms  and  comfortable  living  room    .     . 

10 
IO 

Convenient  kitchen  

IO 

Bathroom,  hot  and  cold  water    
Heating  plant  adequate     

10 
IO 

House  new       

IO 

House  in  good  repair     

10 

13.    THE    HOME    GROUNDS   OR   PARKS,    PLAY- 
GROUNDS, AND  LIBRARY 
(See  pages  295  and  296)      .     .     .     .    .  .  .. 

53 

14.    MY  HOME  GARDEN 
General  appearance       •  ;  •. 
Choice  of  vegetables      

IO 
10 

IO 

Evidence  of  planning    .     . 

5 

Care  of  tools   

5 

Valve  of  produce      ... 

IO 

15.    DEVICES  FOR  CONVENIENCE  AND  LABOR  SAV- 
ING IN  MY  HOME 
Electric  and  gas  devices     
Cleaning  helps      
Kitchen  helps       
Other  helps  :  sewing  machine,  telephone,  etc. 
Tools  and  work  room    

15 

10 
10 
10 

5 

1  6.    MY  INDOOR  RECREATIONS 
Score  based  on  points  mentioned  in  Chapter 
XXIV.     See  Score  Card,  page  388  .     .     . 

SO 

17.    MY  OUTDOOR  RECREATIONS 
Score  based  on  points  mentioned  in  Chap- 
ter XXV.     See  Score  Card,  page  407  .     . 

50 

GRAND  TOTAL  

1000 

38  THE  ESSENTIALS  OF  AN  IDEAL  HOME 

Why  not  undertake  as  a  special  project  the  improvement  of 
the  series  of  score  cards,  with  addition  to  or  subtraction 
from  this  list. 

REFERENCE  BOOKS 

Allen,  Civics  and  Health  (Advanced).     Ginn  and  Company. 

Conn,  Bacteria,  Yeasts,  and  Molds  of  the  Home.     Ginn  and  Company. 

Davison,  Human  Body  and  Health.     American  Book  Company. 

Hunter,  A  Civic  Biology,  Chapter  II.     American  Book  Company. 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapter  II.  American  Book  Com- 
pany. 

Jewett,  Town  and  City.     Ginn  and  Company. 

Tolman,  Hygiene  for  the  Worker.     American  Book  Company. 

Van  Rensselaer  —  Rose  —  Canon,  Manual  of  Home  Making  (Teacher's  use),  Chap- 
ters I,  II.  The  Macmillan  Company. 


CHAPTER   III 
NATURAL  RESOURCES   OF  HOME   ENVIRONMENT 

Problems.  —  i .    What  things  about  us  do  we  get  directly 
from  nature? 

2.  What  is  air,  and  how  does  it  satisfy  a  human  need? 

3.  How  are  we  dependent  upon  the  sun? 

4.  Why  are  water  and  food  of  such  importance? 

Experiments.  —  i.   To  show  the  reality  of  the  air. 

2.  To  prepare  and  observe  the  properties  of  the  principal  gases  in  the 
air. 

3.  To  show  what  part  of  the  air  is  oxygen. 

Project  I.  —  To  MAKE  A  HOME  LABORATORY. 

1.  A  suitable  space  and  table. 

2.  What  source  of  heat?  • 

3.  How  arrange  to  collect  gases? 

4.  What  equipment  needed  to  start  ? 

5.  Cost? 

Project  II.  —  To  DISCOVER  AND  REMEDY  ANY  HARMFUL  EFFECTS  OF 

AIR  ABOUT  THE  HOME  PREMISES. 

1 .  Look  for : 

a.  Decaying  timbers,  boards,  and  trees. 

b.  Rusting  iron,  hinges,  fences,  screens,  tools,  and  stovepipe. 

c.  Tarnishing  metal  as  copper  and  silver. 

d.  Any  other  changes  observed  due  to  air. 

2.  To  find  out  the  proper  way  to  prevent  and  to  correct  the  harm. 

3.  Apply  the  remedy. 

39 


40    NATURAL  RESOURCES  OF  HOME  ENVIRONMENT 


Suggested  Projects. 

1.  TO  PRODUCE   AN  ARTIFICIAL  AIR  AND  COMPARE  ITS  PROPERTIES 
WITH  NATURAL  AIR. 

2.  TO    MAKE    A    STILL     AND     PRODUCE    DISTILLED   WATER     IN    MY 
HOME  LABORATORY. 

3.  TO  PRODUCE  FIRE  BY  SOME  PRIMITIVE  MEANS. 


35 


1000 


DensU 
1 


30000 


What  is  environment  ?- 
Every  boy  and  girl,  yes,  and 
every  living  plant  and  animal, 
no  matter  where  they  live,  come 
in  contact  with  certain  things  in 
their  surroundings.  Air  is  every- 
where around  us.  Light  is  nec- 
essary to  us,  so  much  so  that 
we  use  artificial  light  at  night. 
We  live  either  on  soil  in  the 
country,  or  if  in  the  city,  we 
come  in  contact  with  the  hard 
and  often  dirty  paving  stones 
and  sidewalks.  Water  and  food 
are  both  necessary.  If  the  tem- 
perature falls  below  a  certain 
point,  we  put  on  heavier  clothes. 
Heat,  then,  is  evidently  a  neces- 
sary factor  or  part  of  our  sur- 
roundings. All  these  things  to- 
gether, air,  water,  heat,  light, 
food,  soil,  and  the  living  things 
that  surround  us,  make  up  our 
environment. 

Living   in   an   ocean  of  air.  —  We  are   all  fully  aware 
every  day  that  air  is  about  us.     We  live  in  an  ocean  of  air, 


10 


3-75 


The  ocean  of  air. 


LIVING  IN  AN  OCEAN  OF  AIR 


or,  in  fact,  at  the  bottom  of  it.  We  know  that  it  surrounds 
us,  for  does  not  moving  air  turn  our  windmills,  blow  off  our 
hats,  blow  out  lights,  uproot  trees,  and  even  wreck  houses 
and  whole  settlements  at  times  ? 

We  know  that  air  occupies  space,  for  if  we  force  an 
"  empty  "  glass  upside  down  into  a  pan  of  water,  we  find 
that  the  water  does  not 
enter  the  "  empty  "  space. 
We  know  that  air  is  capable 
of  holding  things  up.  It 
pushes  against  our  kites.  It 
holds  up  balloons.  It  even 
holds  up  the  moving  heavier- 
than-air  machines,  or  air- 
planes. The  first  man  who  ever  flew  in  an  airplane  took  his 
simple  machine  to  the  crest  of  a  hill,  up  which  a  strong  wind 
was  blowing.  He  then  launched  the  glider,  for  there  were  no 
motors  used  at  first  in  the  air,  and  the  force  of  this  air 
against  the  flat  wings  of  the  machine  held  him  up  for  a  time. 

We  may  see  further  evidence  that  air  is  a  real  substance 
by  performing  the  following  experiment. 


Is  the  glass  really  empty  ? 


Clccnv-p 


Experiment.  —  To  show  the  re- 
ality of  air. 

Materials:  Eight-ounce 
wide-mouth  bottle.  Two- 
hole  rubber  stopper. 
Funnel.  Glass  tube. 
Rubber  tube.  Clamp. 
Beaker. 

Method :  Arrange  the  ap- 
paratus as  in  diagram. 

Observations  and  Conclu- 
sions :  When  the  clamp  is 
closed  why  does  the 


42     NATURAL   RESOURCES   OF   HOME   ENVIRONMENT 

water  remain  in  the  funnel?  If  the  mouth  of  the  tube  M  is  deep 
in  the  water  when  the  clamp  is  opened,  and  the  water  runs  out  of  the 
funnel,  what  evidence  do  you  see  to  prove  that  something  is  leaving 
the  bottle? 

What  air  really  is. — Were  any  one  of  us  to  think  over  all 
the  possible  uses  of  air,  we  would  probably  say  its  most  im- 
portant use  is  in  the  human  body,  for  do  we  not  all  use  air 
in  breathing?  But  is  breathing  anything  like  burning? 
Experiments  may  help  us  to  find  this  out.  If  we  cover  a 
burning  candle  with  a  glass  tumbler  or  cheese  dish  we 
notice  that  the  candle  goes  out  in  a  short  time.  If  we 
uncover  the  candle  and  light  it  again  it  will  go  on  burning. 
If  we  cover  it,  it  goes  out  again  as  before.  It  is  evident  that 
some  change  takes  place  in  the  air  during  the  burning  of  the 
candle.  Perhaps  something  in  the  air  is  necessary  for  the 
burning  and  it  is  quickly  decreased  when  we  limit  the 
supply  of  air  by  inclosing  a  burning  candle  in  the  tumbler. 

We  are  told  by  men  who  have  analyzed  air  that  about  99 
per  cent  of  it  is  made  up  of  the  two  gases,  oxygen  and  nitro- 
gen. If  we  prepare  these  gases  and  study  their  properties,  it 
may  help  us  to  explain  the  part  that  the  air  plays  in  burn- 
ing matter  and  in  supporting  life  and  also  to  show  us 
whether  it  is  the  oxygen  or  the  nitrogen  which  is  used 
in  these  processes. 

Experiment.  —  To  prepare  and  to  observe  the  properties  of  the  principal 

gases  in  the  air. 
i.  OXYGEN 

Materials:  Small  wide-mouth  bottle  or  glass.     Glass  cover.     Wood 

taper.     Oxone.     Candle. 

Method:  Drop  a  piece  of  oxone  about  half  an  inch  square  into  the 
glass  tumbler  containing  a  small  amount  of  water.  Light  the  wood 
taper.  Blow  out  the  flame,  leaving  a  glowing  coal  at  the  end. 
Thrust  this  into  the  glass.  Name  the  characteristic  property  of 
oxygen  shown ¥  Will  the  candle  burn  in  oxygen? 


WHAT  AIR  REALLY  IS 


43 


CARBON  DIOXIDE 

Materials:  Vinegar  (or  hydrochloric  acid).  Baking  soda  (or  lime- 
stone). A  glass  or  beaker.  Glass  cover.  Wood  taper.  Lime 
water.  Test  tubes. 

Method:  Pour  two  tablespocnfuls  of  vinegar  upon  a  teaspoonful  of 
soda  in  the  glass.  Cover  immediately.  After  a  minute  or  two 
slide  the  cover  to  one  side  and  thrust  a  burning  taper  into  the 
glass.  Produce  carbon  dioxide  in  a  test  tube.  Hold  the  mouth  of 
this  tube  at  an  angle  over  the  mouth  of  a  second  tube  contain- 
ing some  lime  water.  Carbon  dioxide  will  flow  into  the  lower  tube. 


After  a  minute  or  two,  close  the  lime  water  tube  with  the  thumb 
and  shake.     This  is  the  lime  water  test. 

Observation  and  Conclusion:  What  characteristic  property  of  carbon 
dioxide  does  this  show?  Result  of  lime  water  test? 

NITROGEN 

Materials:  Bunsen  burner.  Test  tubes.  Rubber  stopper.  Delivery 
tube.  Shallow  dish.  Small  wide-mouth  bottle.  Wood  taper. 
Ammonium  nitrite.  Lime  water. 

Method:  Heat  ten  grams  of  ammonium  nitrite  in  test  tube  and  col- 
lect Jthe  gas  by  displacement  of  water  as  shown  in  the  diagram. 
When  the  bottle  is  full,  cover  and  remove  from  the  water.  Open 
and  thrust  a  burning  taper  into  it.  Apply  the  lime  water  test. 

Observation  and  Conclusion:  Does  nitrogen  resemble  oxygen  or  carbon 
dioxide  in  its  relation  to  fire? 


44     NATURAL  RESOURCES  OF  HOME  ENVIRONMENT 


What  makes  the  candle  burn  ?  —  If  we  were  to  place  a 
lighted  candle  in  the  jar  in  which  the  candle  went  out 
(page  42),  we  would  find  that  it  does  not  burn.  Evidently 
some  part  of  the  air  caused  that  candle  to  burn.  Let  us 
try  to  find  out  whether  it  is  the  oxygen.  We  have  seen 
that  wood  burns  in  oxygen  and  we  guess  that  it  is  oxygen 
that  makes  it  possible  for  the  candle  or  splinter  to  burn 
in  the  air.  Suppose  we  introduce  some  oxygen  into  the 
glass  in  which  the  candle  will  not  burn.  After  mixing 
we  insert  a  lighted  candle  and  find  that  it  does  burn,  act- 
ing very  much  as  it  did  in  the  open 
air.  The  mixed  gases  in  the  tumbler 
evidently  help  the  candle  to  burn. 
There  can  now  be  no  doubt  that  the 
oxygen  of  the  air  is  needed  to  make 
the  candle  burn.  It  is  equally  es- 
sential to  us  in  breathing  as  we  shall 
learn  a  little  later. 

Those  of  you  who  have  started 
a  home  laboratory  will  be  interested 
to  collect  oxygen  in  bottles  and  to 
burn  other  substances  in  it,  as  sul- 
phur and  iron.  For  burning  iron 
use  picture  cord  wire.  Unravel  the 
end,  warm,  dip  in  sulphur,  light 
the  sulphur,  and  thrust  into  the  jar 
of  oxygen. 

Still  another  gas  in  the  air.  —  If  we  were  to  leave  a  jar 
containing  limewater  in  the  open  air  overnight,,  we  would 
find  in  the  morning  a  whitish  film  on  the  surface  of  the 
liquid.  If  we  prepare  a  gas  by  pouring  a  little  vinegar  or 
hydrochloric  acid  upon  cooking  soda  and  pass  it  through 


The  limewater  test  for  carbon 
dioxide. 


WATER  IN  THE  AIR 


45 


limewater,  we  find  that  the  liquid  becomes  milky  in  ap- 
pearance. If  we  shake  a  little  limewater  in  the  jar  after 
burning  wood  or  a  candle  in  it,  we  find  that  the  lime- 
water  turns  milky.  Evidently  we  might  use  this  test, 
known  as  the  limewater  test,  to  prove  the  presence  in 
the  air  of  a  gas  formed  when 
certain  things  are  burned.  Do 
you  see  why  ?  The  chemist  tells 
us  that  this  gas  which  is  pro- 
duced by  mixing  soda  and  vine- 
gar is  carbon  dioxide.  He  uses 
limewater  to  test  for  the  pres- 
ence of  carbon  dioxide.  Carbon 
dioxide  is  formed,  as  we  shall  find 
later,  by  the  union  of  oxygen 
and  a  substance  called  carbon 
when  anything  containing  car- 
bon is  burned.  Carbon  dioxide 
is  always  present  in  the  air,  al- 
though in  very  small  amounts, 
about  .04  per  cent  in  out-of-door 
air.  It  is  constantly  being  given 
off  into  the  air  by  decaying  vegetable  matter,  by  burning 
fuels,  and  by  breathing  animals.  * 

Water  in  the  air.  —  Air  is  really  a  very  complex  sub- 
stance, and  contains  besides  the  gases  mentioned,  more 
or  less  water.  You  can  easily  prove  this  by  mixing  a 
little  salt  with  ice  in  a  test  tube,  and  observing  the  little 
drops  of  moisture  which  form  on  the  outside  of  the  tube. 
Where  does  it  come  from  ?  In  addition  to  water,  several 
gases,  among  them  argon,  are  found  in  small  quantities  in 
the  air. 


This  shows  that  water  is  present 
in  the  air. 


46     NATURAL  RESOURCES  OF  HOME   ENVIRONMENT 


There   is  dust  in  practically  all   the  air   we 
breathe. 


Impurities  in  the  air. 
If  you  allow  a  beam  of 
sunlight  to  pass  through 
a  small  crack  into  a 
darkened  room,  you  will 
see  thousands  of  tiny 
specks  floating  in  the  air. 
These  little  particles  are 
perhaps  soot,  dust,  or 
other  bodies.  In  some 
cities,  like  Pittsburgh, 

the  smoke  is  always  a  constant  factor,  although  it  does 

not  seem  to  harm  people  very  much,  but  where  factories 

are  numerous,  we  sometimes  get  poisonous  fumes  or  gases 

as  part  of  the  air  we 

breathe. 

Combustion. —  We 

have  seen  from  the 

experiments  we  have 

performed  that  when 

the    gas    oxygen    is 

present,   wood   or   a 

candle    may    be 

burned.     Heat     and 

light  always  accom- 
pany   this    burning. 

Combustion  or  burn- 
ing in   pure   oxygen 

is  much  more  intense 

than    it    is    in    air. 

Iron  and  other  metals 

can    be    burned    in 


What  kinds  of  oxidation  are  shown  here  ? 


WATER 


47 


pure  oxygen,  while  in  ordinary  air  the  nitrogen  dilutes  the 
oxygen  and  thus  weakens  its  action. 

Oxidation.  —  In  the  series  of  experiments  we  have  just 
performed,  burning  was  simply  a  union  of  oxygen  with  the 
substances  burned,  but  all  around  us  this  union  with  other 
substances  is  taking  place  without  producing  any  flame. 
You  are  all  familiar  with  the  fact  that  iron  rusts.  This 
is  caused  by  the  union  of  iron  with  oxygen. 
Such  oxidation  is  relatively  a  slow  oxidation. 
A  similar  process  of  oxidation  attends  the 
decay  of  organic  matter.  In  the  case  of 
combustion  the  action  is  much  more  rapid, 
and  both  heat  and  light  are  given  off. 

Water.  —  Every  boy  and  girl  knows  that 
water  is  necessary  for  the  life  of  both  plants 
and  animals.  This  can  easily  be  proved  by 
allowing  some  living  plant  to  wilt,  and  then 
adding  a  moderate  amount  of  water  to  the 
pot  in  which  it  grows.  What  causes  the 
leaves  to  raise  themselves?  We  say  that 
the  plant  takes  up  water.  This  is  true,  al- 

.  1-1  Amount   of    water 

though  we  cannot  at  this  time  explain  what  in  the  human 
happens  inside  of  the  plant.  Any  boy  or 
girl  who  has  had  to  go  without  water  for  several  hours 
knows  how  necessary  it  is  and  how  uncomfortable  one 
can  be  without  it.  In  the  World  War  water  played 
a  striking  part,  especially  in  General  Allenby's  campaign 
against  the  Turkish  army  in  Palestine.  The  Turks  had  a 
saying  that  "  The  Christians  will  not  capture  Palestine 
until  the  Nile  flows  into  the  Jordan."  This  meant,  of 
course,  that  they  would  never  capture  it,  because  the 
Turks  believed  that  such  a  thing  was  impossible.  But 


48     NATURAL  RESOURCES  OF  HOME  ENVIRONMENT 


when  General  Allenby's  army  marched  across  the  desert 
into  Palestine,  the  British  engineers  built  a  pipe  line 
which  actually  did  carry  water  from  the  Nile  under  the 
Suez  Canal  and  supplied  the  army  in  the  desert  with 
fresh,  pure  water,  so  the  saying  of  the  Turks  was  carried 
out  almost  as  if  it  had  been  a  prophecy. 

No  one  would  think  of  building  a  house  or  locating  where 
there   is  no    supply  of    water,  and   modern   science   has 

shown  that  pure 
water  is  one  of  the 
greatest  factors  in 
good  health.  Be- 
sides using  water  at 
home  for  washing, 
and  sprinkling  the 
lawn,  we  use  it  in 
the  form  of  ice  and 
as  steam  or  hot 
water  to  heat  our 
houses,  to  turn  mo- 
tors which  generate 
power  and  save  la- 
bor, and  in  many 
other  ways  of  which 
you  can  think.  Why  not  try  to  find  out  how  many  ways 
water  can  be  used  by  man  in  the  home?  This  would 
make  an  excellent  home  project.  But  in  addition  to  these 
uses,  the  human  body  needs  water,  first  because  a  very 
large  percentage  of  it,  about  65  per  cent,  is  made  up  of 
water.  Furthermore,  in  order  that  foods  may  become  part 
of  the  body  they  must  first  be  dissolved  in  water  and  soak 
through  the  walls  of  the  food  tube  to  become  part  of  the 


Cells  are  the  units  of  building  material  in  the  human 
body  as  bricks  are  of  the  house. 


WHAT  IS  SOIL? 


49 


blood  and  in  this  form  go  to  the  various  cells  or  units  of 
building  material  in  the  body.  In  addition  to  this,  water 
is  necessary  in  order  to  get  rid  of  the  wastes  of  the  body. 
These  wastes  must  also  be  dissolved  in  water  and  carried 
off  in  it,  so  that  water  plays  an  important  part  in  our  lives. 
What  is  soil  ?  —  To  the  average  boy  and  girl  brought 
up  in  a  large  city,  the  word  soil  does  not  mean  much. 

Sometimes     they     may     | ; — } 1 

play  on  vacant  lots  or 
go  to  the  parks  where 
they  see  dirt  or  soil,  but 
they  come  in  contact 
with  it  less  frequently 
than  the  country  boy  to 
whom  soil  means  hard 
work.  Gardens  depend 
on  soil.  They  must  be 
weeded  and  attended 
to.  Crops  grow  in  soil. 
They  must  be  culti- 
vated. Fruit  trees  grow 
in  soil.  They  require  much  care.  To  understand  what 
soil  really  is  and  how  it  came  to  be,  we  must  look  back  a 
great  many  million  years.  Long  ago,  we  are  told,  the  earth 
was  a  great  white-hot  mass  of  rapidly  revolving  material. 
As  this  mass  cooled  the  greater  part  of  it  became  rock. 
Later  the  rock,  alternately  expanding  with  heat  and  con- 
tracting with  cold,  began  to  crack  and  crumble  so  that 
little  fragments  were  formed.  These  pieces  were  ground 
up  by  the  action  of  ice  and  running  water,  and  the  atmos- 
phere caused  them  to  decay.  Gradually  this  covering  of 
tiny  pieces  of  rock  became  soil.  Examination  of  beach 

H.-WHIT.    CIV.    SCI.    IN    THE   HOME  —  4 


Formation  of    inorganic    soil.     (After    Black- 
welder  and  Barrows.) 


50     NATURAL  RESOURCES   OF  HOME   ENVIRONMENT 

sand  or  river  gravel  will  show  you  how  small  particles  of  soil 
might  thus  be  formed. 

After  plants  and  animals  began  to  live  on  the  earth,  their 
dead  bodies,  upon  decaying,  became  a  part  of  the  soil. 
Any  boy  who  has  been  in  a  forest  knows  that  the  soil  is 
covered  with  dead  leaves,  decaying  wood,  and  the  like. 
He  also  knows  that  if  he  digs  down  through  the  tangled 


Formation  of  organic  soil  or  humus.     (U.  S.  Forest  Service.) 

mass  of  roots  and  other  materials  forming  black  rich  soil,  he 
may  at  last  come  to  sand  or  to  crumbling  rock. 

Soil  and  the  home.  —  Soils  play  a  very  important  part 
in  the  health  of  our  home.  If  the  soil  is  of  sand  and  not 
clay,  water  will  drain  readily,  and  we  shall  not  be  troubled 
with  standing  bodies  of  water  after  rains.  Our  garden 
will  grow  better  and  conditions  of  drainage  will  be  good. 
We  shall  later  see  that  the  fertility  of  the  garden  depends 
largely  upon  the  kind  and  composition  of  soil,  and  this 
means  that  the  home  grounds  may  or  may  not  be  attrac- 


THE  SUN  AND  RAYS  OF  HEAT 


tive,  depending  on  the  kind  of  soil.  We  shall  find  later  that 
the  soil  of  the  garden  or  lawn,  instead  of  being  dead  as  we 
thought,  is  really  a  battlefield  in  which  millions  of  little 
germs  are  engaged,  some  in  causing  decay  of  materials 
there,  others  in  making  the  decaying  material  available  or 
valuable  for  plants  in  the  form  of  nitrogen  compounds, 
while  still  others 
break  down  these 
nitrogen  compounds 
and  allow  some  of 
the  nitrogen  to  pass 
off  into  the  air. 

Light  and  heat.  — 
What  would  you  do 
without  light?     We 
must  all  realize  the  The  effect  of  light  upon  a  growing  plant 

importance  of  light  when  we  remember  how  much  artificial 
light  means  to  us  in  our  homes.  All  green  plants  need 
light.  Notice  the  geranium  or  oxalis  growing  in  your  win- 
dow garden.  The  stems  turn  to  the  light,  and  expose  as 
much  leaf  surface  as  possible  to  the  sun's  rays.  Without 
light  no  green  plant  can  exist,  and  without  green  plants 
no  animals  can  exist.  Think  this  over  and  see  if  it  is  not 
true.  Your  beefsteak  came  from  a  cow  which  lived  upon 
grass  which  grew  as  a  result  of  having,  among  other  things, 
sunlight.  .  You  know,  too,  there  can  be  no  life  without 
heat. 

The  sun  and  rays  of  heat.  —  Have  you  ever  stopped  to 
think  why  it  is  warmer  in  summer  than  in  winter  ?  A  glance 
at  the  diagram  on  page  52  will  show  you.  The  sun's 
rays  come  more  directly  upon  us  in  summer,  and  give  us 
more  heat.  If  you  do  not  believe  the  sun  gives  off  heat, 


52     NATURAL   RESOURCES   OF  HOME   ENVIRONMENT 


use  a  burning  glass  on  your  fingers  instead  of  on  a  piece 
of  paper.  This  heat  or  energy  is  more  useful  than  we  at 
first  are  aware.  Energy  is  the  power  to  do  work.  The  sun 


How  the  sun's  position  varies  throughout  the  year.     Does  it  help  explain  our  cold 
winters  and  warm  summers  ?    (After  Todd.) 

works  for  us  in  many  ways,  and  the  most  wonderful  of 
all  is  the  making  of  food  by  green  plants.  The  length  of  time 
that  the  sun  works  for  us  depends  upon  the  section  of 


Notice  that  the  beam  of  sunlight  covers  a  smaller  area  of  the  earth's  surface  at  noon 
than  at  any  other  time. 

the  country  in  which  we  live.     Study  the  sunshine  chart 
to  see  how  much  sunshine  you  have  in  your  own  locality. 


FOODS 


53 


Foods.  —  Another  resource  of  our  environment  is  food. 
We  know  that  when  we  are  hungry  we  eat,  but  we  cannot 
tell  why,  nor  can  we  tell  what  the  foods  do  for  us.  This 
will  be  the  subject  of  a  later  lesson.  All  we  need  to  know 
now  is  that  these  foods  which  are  taken  into  our  bodies 
may  be  used  for  two  purposes,  to  build  more  body  material, 
and  to  release  energy  or  work  power  in  the  body.  We  grow 


up  to  about  the  age  of  twenty,  and  may  increase  in  weight 
after  that,  but  it  is  not  easy  for  us  to  realize  that  the 
food  we  take  into  our  bodies  must  actually  be  oxidized  or 
burned  in  order  to  release  energy  or  work.  But  if  we  think 
back  to  one  of  our  former  experiments,  this  is  not  so  diffi- 
cult to  understand.  You  remember  that  when  limewater 
turned  milky,  it  was  a  test  that  carbon  dioxide  had  been 
released,  or  that  something  containing  the  element  carbon 
had  been  oxidized.  If  we  expel  air  from  our  lungs  into  a 
jar  of  limewater  we  notice  that  in  a  very  short  time  the 


54     NATURAL  RESOURCES  OF  HOME  ENVIRONMENT 

limewater  becomes  milky  in  color.  From  former  experi- 
ments, it  is  evident  that  oxidation  must  be  taking  place  in 
our  bodies.  It  would  not  require  much  of  a  stretch  of  one's 
imagination  to  think  out  this  whole  process,  and  in  this  way 
compare  our  own  bodily  machine  to  that  of  an  engine. 
Coal  may  be  the  source  of  power  to  drive  the  engine.  In 
the  case  of  our  bodily  machine,  what  is  it  that  corresponds 
to  the  coal  of  the  mechanical  machine? 

Scoring  my  environment.  —  The  following  score  card  is 
a  tentative  project.  We  shall  find  much  in  the  future  chap- 
ters of  this  book  and  its  companion  book  on  Civic  Science  in 
the  Community  that  may  cause  us  later  to  wish  to  change 
our  score.  You  may  think  of  other  items  to  score  that  seem 
more  important  to  you.  If  so,  make  a  score  card  of  your 
own.  Modify  any  of  the  conditions  here  that  you  think 
ought  to  be  changed  and  bring  your  suggestions  into  class 
as  a  problem  for  discussion.  Get  help  at  home  where  you 
need  it  on  this  card  and  above  all,  try  to  be  honest  in 
your  estimates.  Remember  you  do  not  cheat  anybody 
but  yourself  in  a  score  which  you  know  is  incorrect. 

REFERENCE  BOOKS 

Barber,  First  Course  in  General  Science,  Chapter  II.    Henry  Holt  and  Company. 

Blackwelder  and  Barrows,  Elements  of  Geology.     American  Book  Company. 

Caldwell  and  Eikenberry,  General  Science,  Chapters  II,  VI,  VIII.  Ginn  and 
Company. 

Clark,  Introduction  to  Science,  Chapter  IV.     American  Book  Company. 

Dorrance,  The  Story  of  the  Forest.     American  Book  Company. 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapter  II.  American  Book  Com- 
pany. 

Smith  and  Jewett,  Introduction  to  the  Study  of  Science,  Chapter  II.  The  Macmillan 
Company. 

Trafton,  Science  of  the  Home  and  Community.     The  Macmillan  Company. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Projects  II,  III,  IV.  Hough- 
ton  Mifflin  Company. 

Weed,  Chemistry  in  the  Home,  Chapters  II,  VII,  IX.    American  Book  Company. 


SCORING  MY  ENVIRONMENT 


55 


SCORE  CARD.  THE  NATURAL  RESOURCES  OF  MY  ENVIRONMENT 


EXCELLENT 

FAIR 

VERY  POOR 

MY  SCORE 

Total 

AIR 

Air  pure 
No  dust  (2) 
No  smoke  (2) 
No  bacteria  (2) 

No  odors  (2) 

Much  vegetation 
in  vicinity  (2) 

Air  contains  dust  at 
times  (i) 
Some  smoke  (i) 
Some  bacteria  (i) 
Some  odor  or  dan- 
gerous fumes  (i) 
Parks  (i) 
Public  play- 
grounds (i) 

Air  has  much  dust  (o) 

Smoke  at  all  times  (o) 
Many  bacteria  in 
air  (o) 
Much  odor  or  poison- 
ous fumes  (o) 
No  parks  or  play- 
grounds (o) 

WATER 

(City  boy 
and  girl 
score   10 
if  in  a 
city  with 
good 
protected 
water 
supply) 

Spring  or  well 
tested  by  bac- 
terial expert; 
driven  or  ar- 
tesian well;  all 
protected  at 
'surface  (8) 
Rain  water  pro- 
vided in  cement 
cistern;  no 
vegetable  mat- 
ter in  supply  (2) 

Spring  or  well  not 
recently  tested. 
Protected  by 
cement  curbing. 
No  privy  or  cess- 
pool within  100 
ft.  (4) 
Rain  water  in  tank 
or  barrel;  no  ce- 
ment (i) 

Spring  or  well  not 
properly  protected. 
Cesspool  or  privy 
within  100  ft.  (o) 

No  rain  water,  or  bar- 
rel open  with  wig- 
glers  in  it  (o) 

SOIL 

(City  girl 
and  boy 
score  10 
if   living 
in  apart- 
ment) 

Soil;   sandy  loam 
(3) 
House  high, 
drainage    from 
house  (3) 
No  pools  or 
standing  water 
(2) 
Cellar  always 
dry  (2) 

Soil;  sandy  and  dry 
or  part  clay  (2) 
House  level  with 
street,     drainage 
fair  (2) 
Pools  of  water 
sometimes  after 
rain  (i) 
Cellar    sometimes 
damp  (i) 

Soil;  clay  (o) 

Drainage  poor,  house 
below  street  level  (o) 

Standing  water  after 
rain  (o) 

Cellar  always  wet  (o) 

WEATHER 

Sunlight  50%  of 
the  time  (4) 
Temperature 
rarely  over  95° 
or  under 

-20°F.   (3) 

No  damaging 
floods  or  severe 
drouth  (3) 

Sunlight    40%    of 
the  time  (2) 
Temperature  rarely 
above  100°  or  be- 
low —30°  F.  (2) 

Occasional  damage 
by  floods  or 
severe  drouths  (i) 

Sunlight  under  40% 
of  the  time  (o) 
Temperature  rarely 
more  than   105°  or 
below—  40°  F.(o) 

Frequent    damage 
from  floods  or 
drouths  (o) 

FOODS 

Home   supply   of 
fruits,  vege- 
tables, eggs, 
and  poultry  (5) 
Food  purchased 
reaches  home 
in  sanitary  con- 
dition and 
fresh  (3) 
Foods  relatively 
cheap  (2) 

Home  supply  of 
either  fruits  and 
vegetables  or  eggs 
and  poultry  (3) 
Food  purchased  _ 
reaches  home  in 
fair  condition, 
not  always  fresh 
d) 
Foods  moderate  in 
cost  (i) 

No  home  supply   of 
foods;    no  garden, 
or  chickens  kept  (o) 

Foods  neither  sani- 
tary nor  fresh  (o) 

Foods  expensive  (o) 

GRAND   TOTAL 

NOTE:  You  are  expected  to  pick  out  the  items  that  you  think  cover  your  conditions  and 
score  under  proper  column.  For  example,  if  food  supply  was  all  purchased  but  was  sanitary, 
fresh,  and  cheap,  you  would  score  (o),  (3),  and  (2)  respectively.  Do  not  fill  m  the  above 
blank,  but  make  a  similar  score  card  in  your  notebook. 


PART    II.     GOOD   HEALTH    IN  THE 

HOME 

CHAPTER  IV 
PURE  AIR 

Problems.  —  i.  To  understand  how  and  why  we  breathe 
air. 

2.  To  understand  the  need  of  ventilation  and  how  to  ven- 
tilate our  rooms. 

Experiments.  —  i.   Does  air  have  weight? 

2.  To  illustrate  the  process  of  breathing. 

3.  To  determine  some  products  of  respiration. 

4.  To  demonstrate  .the  principles  involved  hi  ventilation. 

Project  I.  —  CAN  I  INCREASE  MY  LUNG  CAPACITY  WITHIN  TEN 

WEEKS  ? 

1.  What  is  my  chest  expansion  at  the  present  time? 
Take  measure  under  the  arms,  clothing  removed. 

(1)  After  taking  a  good  normal  breath. 

(2)  After  exhaling  a  normal  breath. 

(3)  After  filling  the  lungs  as  full  as  possible. 

(4)  After  forcing  all  the  air  possible  from  the  lungs. 
The  difference  between  (3)  and  (4)  is  the  chest  expansion. 

2.  Make  a  tabular  form  for  recording  these  four  measurements 
and  the  chest  expansion.     Take  weekly  measurements  for  ten  weeks. 

3.  Find  out  what  exercise  is  good  to  develop  the  lungs  and  prac- 
tice it  faithfully  each  day. 

56 


PROJECTS  57 

4.  From  the  weekly  reports  kept  make  a  graph  to  show  the 
changes  in  your  chest  expansion  during  the  ten-week  period. 

Make  a  report  explaining  what  exercises  you  have  used,  and  in- 
clude tables  and  graph. 

Have  you  experienced  any  ill  effects  or  any  beneficial  effects  from 
this  work? 

Note :  If  desired,  actual  lung  capacity  may  be  tested  with  a  spirometer, 
though  the  measurements  suggested  give  satisfactory  results. 

Project  II.  —  How  TO  SECURE  PURE  AIR  IN  MY  BEDROOM. 

1.  What  methods  are  used  in  ventilating  ? 

How  do  my  friends  ventilate  their  rooms,  —  windows  open  at 
top,  at  bottom,  at  both  top  and  bottom;  two  windows  open? 
Open  doors  to  help  air  circulation.  Dust  annoyance.  Advan- 
tage and  disadvantage  of  thin  muslin  or  cheesecloth  windows. 
Deflecting  devices.  Screens  in  room  to  deflect  drafts. 

2.  Need  of  fly  and  mosquito  screening  the  entire  length  of  win- 
dow. 

3.  Plan  of  room  showing  arrangement  of  essentials. 
Indicate  with  arrows  probable  movement  of  air. 
Effect  of  winds;  direction  of  wind;  no  winds. 

4.  Make  a  complete  report  of  your  investigation,  illustrating  with 
diagrams,  clippings,  and  pictures  from  papers  and  magazines. 

Give  specifically  best  plan  for  ventilating  your  own  bedroom. 

Project  III.  —  To  PREPARE  FOR  LIFE  SAVING  WHERE  ARTIFICIAL 

RESPIRATION  MUST  BE  USED. 

1.  You  must  qualify  as  a  good  swimmer. 

2.  You  must  understand   dangers   from   "live"  electric  wires, 
and  how  to  remove  the  shocked  person  from  such  wires. 

3.  You  must  know  how  to  rescue  a  person  in  water. 

4.  You  must  be  able  to  use  the  Shaefer  method  of  artificial  res- 
piration. 

Reference:  American  Red  Cross  Abridged  Textbook  on  First  Aid, 
Blakiston,  or  Boy  Scout  Manual. 

When  you  feel  qualified  for  this  work,  write  a  report  on  what 
you  can  do,  and  how  you  would  act  in  case  of  accident  requiring 
artificial  respiration. 


PURE  AIR 


Suggested  Project. 

I.    TO    MAKE    A    SUBSTITUTE    FOR    THE    SPIROMETER    WHICH    YOU 
CAN   USE   IN   TESTING    YOUR   LUNG    CAPACITY. 

Thought  Questions. 

1.  Do    you    breathe   normally   immediately   after   holding   the 
breath  as  long  as  possible  ? 

2.  Can  you  "  hold  your  breath  "  longer  with  lungs  inflated  or 
deflated?     Why? 

Why  is  pure  air  necessary  ?  —  This  is  an  age  when  people 
seem  to  recognize  the  necessity  of  pure  air  for  healthy  liv- 

ing.     People  build  houses  with  sun 

parlors  open  to  the  air,  and  with 
sleeping  porches  where  the  entire 
family  may  sleep  winter  and  sum- 
mer. New  laws  require  city  houses 
and  tenements  to  be  built  with  an 
adequate  air  space  so  that  sleeping 
rooms  may  have  a  proper  amount 
of  air  going  in  through  the  windows 
at  night.  We  have  outdoor  school- 
rooms and  both  teachers  and  doc- 
tors preach  the  need  of  proper 
ventilation. 

It  seems  almost  incredible  that 
over  sixty  barrels  of  air  pass  in  and 
out  of  your  lungs  every  day  of 
your  life.  If  you  will  count  the 
number  of  breaths  you  take  in  a 
minute  while  you  sit  quietly  in  the  schoolroom  (number  of 
tunes  your  chest  rises  and  falls),  and  then  if  you  will  exer- 
cise vigorously  for  two  minutes  (a  stationary  run  with  hands 
raised  above  the  head  will  be  a  good  exercise)  and  again 


An  out-of-door  sleeping  porch. 


AIR  PRESSURE  AND  WHAT  IT  IS 


count  the  number  of  times  you  breathe  in  one  minute,  you 
will  notice  a  distinct  increase.  Compare  this  with  the 
forced  draft  in  the  engine.  Evidently  the  body  needs 
more  air  when  we  exercise  than  when  we  sit  quietly,  and 
this  wonderful  human  machine  responds  automatically  to 
its  demands. 

Air  pressure  and  what  it  is.  —  We  are  told  that  air  presses 
down  on  us  with  a  force  of  fifteen  pounds  to  the  square 
inch.  It  is  easy  to  understand  that  water  exerts  pressure 
on  a  vessel  which  contains  it,  but  it  is  more  difficult  to  think 
of  air  as  having  weight  and  so  exerting  pressure.  We  may 
actually  see  in  an  experiment  whether  or  not  air  has  Weight 
by  weighing  a  bottle  before  and  after  pumping  air  out 
of  it. 

Experiment.  —  Does  air  have  weight? 

Materials:  A  two-liter  bottle  with  one-hole  rubber  stopper.     Glass  and 
rubber    tubing.     Burette    clamp.     Mohr    clamp.     Platform    scales. 
Sand  or  weights.    Air 
pump  for  suction  or      _ 

compression.      Vase-     ^=— £^5^=3        ^ 
line. 

Method  and  Observa- 
tions: Pass  the  glass 
tube  through  the  rub- 
ber stopper  and  at- 
tach a  rubber  tube  to 
it.  Place  the  Mohr 
clamp  on  the  rub- 
ber tube.  Set  the  bottle  on  one  arm  of  the  platform  scales  and 
fasten  the  rubber  tubing  to  a  clamp  on  a  ring  stand  leaving  the  tubing 
loose  enough  to  move  freely  up  and  down  with  the  movement  of  the 
balance.  Make  the  stopper  tight  with  vaseline  and  tie  it  in  if  air  is 
to  be  forced  into  the  bottle.  Exactly  balance  the  bottle  by  pouring 
sand  into  a  jar  or  using  weights  on  the  other  balance  arm. 

By  means  of  a  force  pump  attached  to  the  end  of  the  rubber  tube  force 
air  into  the  bottle.  What  is  the  evidence  to  show  if  air  has  weight? 
Disconnect  the  pump  to  open  the  tube  to  the  air.  Result? 


6o 


PURE  AIR 


\foice-  box: 


How  we  breathe.  —  We  all  know  that  somewhere  inside 
of  our  bodies  there  are  spongy  structures  we  call  lungs. 
The  diagrams  (page  70  and  below)  show  us  that  from  the 
mouth  cavity  down  the  front  of  the  neck  leads  a  tube  known 
as  the  air  tube,  or  windpipe,  and  that  this  tube  branches 
into  two  pipes,  or  bronchial  tubes,  which  in  turn  branch 

again  and  again  and 
end  in  tiny  grapelike 
clusters  of  little  air 
sacs,  which  are  too 
small  to  be  seen  with 
the  naked  eye.  In 
these  air  sacs,  which 
have  extremely  thin 
walls,  the  oxygen  of 
the  air  comes  in  con- 
tact with  the  blood, 
the  blood  taking 
some  oxygen  and 
giving  up  in  return 
some  carbon  diox- 
ide, which  has  been 
brought  there  from 
the  various  parts  of  the  body  where  work  is  being  done. 
Around  these  delicate  lungs  are  placed  the  ribs,  so  that  as 
the  diagram  shows,  the  two  lungs  are  held  within  a  sort 
of  bag  or  cavity.  This  chest  cavity  is  bounded  at  the 
bottom  by  a  muscular  wall,  the  diaphragm,  which  extends 
across  from  the  front  to  the  back  of  the  body,  and  makes 
an  air-tight  surface  surrounding  the  lungs.  If  we  now  study 
a  simple  piece  of  apparatus  shown  in  the  picture  on  the  next 
page,  we  shall  be  able  to  understand  how  we  breathe. 


The  human  breathing  organs.    Notice  one  lung  is  cut 
open  to  show  the  air  sacs. 


HOW  WE  BREATHE 


61 


Experiment.  —  To  illustrate  the  process  of  breathing. 

Materials:  A  bell  jar  fitted  with  a  rubber  cork,  and  wide  glass  tubing 
from  the  ends  of  which  are  tied  two  rubber  balloons.  Over  the  lower 
end  of  the  bell  jar  is  tied  a  piece  of  sheet  rubber  such  as  dentists  use, 
with  a  piece  of  string  attached  at  the  middle  outside  the  jar. 

Method:  Pull  on  the  string  so  that  the  cavity  inside  the  jar  is  increased 
in  size.  What  effect  does  this  have  on  the  rubber  balloons  ?  Allow  the 
rubber  diaphragm  to  go  back  to  its  former  position  by  releasing  the 
tension  of  the  string.  What  happens  to  the  balloons?  Why? 

Conclusion:  Explain  the  different  actions  you  have  seen  and  apply 
them  to  the  action  of  breathing.  If  your  finger  were  placed  on  the 
tube  leading  into  the  balloons  and  then  the  rubber  diaphragm  were 
pulled,  do  you  think  the  action  would  be  the  same  ?  Try  it. 


It  is  very  evident  from 
this  experiment  that  the 
air  pressing  in  on  the  bal- 
loons through  the  tube 
causes  them  to  expand. 
If  we  now  compare  this 
apparatus  in  its  working 
with  our  own  lungs,  ribs, 
and  diaphragm,  we  are 
able  to  understand  how 
we  breathe.  If  you  will 
stand  upright  and  take 
a  full  deep  breath,  you 
will  readily  notice  that 
as  your  chest  expands 
the  ribs  rise.  This  makes 


Apparatus  to  show  the  mechanics  of  breathing. 


the  chest  cavity  some- 
what larger.  As  the  ribs  rise  the  muscular  diaphragm 
assumes  a  straighter  line.  The  lungs  lying  in  this  cavity 
are  now  filled  by  the  air  which  rushes  into  the  larger 
space  thus  made.  This  enlargement  of  the  chest  cavity 


62 


PURE  AIR 


and  the  consequent  filling  of  the  lungs  with  air  is  known 
as  an  inspiration.  After  we  have  raised  the  ribs,  we  al- 
low the  muscles  which  pull  them  up  to  relax ;  as  the  ribs 
sink  back  and  the  diaphragm  expands  curving  up  into 
the  chest  cavity,  the  chest  cavity  becomes  smaller  and 
pushes  the  air  from  the  lungs.  This  is  an  expiration. 

Distinction  between  breathing  and  cell  respiration.  — 
Most  boys  and  girls  think  that  breathing  takes  place  in 

the  lungs.  This  is 
true,  but  we  would 
soon  die  if  the  oxygen 
stopped  there.  As  a 
matter  of  fact  the 
lungs  are  simply  or- 
gans which  serve  to 
pass  oxygen  over  to 
the  blood  and  to  take 
carbon  dioxide  and 
waste  matter  from  it. 
The  real  respiration 
takes  place  in  the  cells  of  the  body  which  do  work  for 
us.  If  we  work  the  muscle  of  the  arm,  then  that  muscle 
in  order  to  do  its  work  must  oxidize  some  fuel  or  food 
material  which  has  been  carried  to  it  by  the  blood.  If 
we  work  with  the  brain,  then  food  must  be  oxidized  in 
the  brain  cells  in  order  that  energy  may  be  released  there. 
The  blood,  like  a  railroad  train,  carries  the  oxygen  from  the 
lungs  to  all  places  in  the  body  where  oxygen  is  needed. 
In  the  blood  are  little  cells  known  as  red  corpuscles.  These 
cells  have  the  peculiar  ability  to  carry  oxygen.  They  are 
also  able  to  give  up  this  oxygen  where  it  is  needed  in  the 
body.  Thus  the  blood  becomes  a  medium  of  exchange 


The  respiration  of  cells. 


THE  NECESSITY  FOR  DEEP  BREATHING 


between  the  cells  which  need  oxygen  and  the  air  which  is 
taken  into  the  lungs.  The  products  formed  when  oxygen 
is  used  in  the  body  are  exhaled  in  the  breath  and  may  be 
detected  by  simple  tests. 

Experiment.  —  To  determine  some  products  of  respiration. 

Materials:   Glass  tubing.     Limewater.     Test  tube. 

Method  and  Observations:  Blow  the  breath  through  a  large,  dry  glass 
tube  until  there  is  evidence  of  material  deposited.  From  its  appear- 
ance what  do  you  judge  this  to  be?  Blow  the  breath  through  lime- 
water  in  a  test  tube  for  a  short  time.  What  change  occurs?  Recall 
the  meaning  of  this  test,  which  was  previously  shown  in  Chapter  III. 

Conclusion:  What  are  two  substances  produced  in  our  bodies  which 
escape  in  our  breath? 

The  necessity  for  deep  breathing.  —  The  blood,  too, 
carries  back  to  the  lungs  carbon  dioxide  which  has  been 
formed  in  the  cells 
as  a  result  of  the 
work  done  there,  and 
this  carbon  dioxide, 
as  we  have  seen  by 
our  limewater  test, 
is  expelled  from  the 
lungs  during  respira- 
tion. The  lungs  dur- 
ing ordinary  breath- 
ing do  not  expel 
more  than  one  sev- 
enth of  their  total 
load  of  air.  More 
of  the  air  in  the 


Tidal  air  is  that  air  taken  in  and  expelled  during  ordi- 
nary breathing.  Complemental  air  is  what  we  can 
take  in,  in  addition  to  tidal  air  in  a  full  deep  breath. 
Reserve  air  is  what  we  can  force  out  in  addition  to 
tidal  air  by  forced  expiration.  Residual  air  is  that 
which  always  remains  in  the  lungs. 

air    in 

lungs  can  be  expelled  when  we  take  a  deep  breath,  but 
there  is  always  some  air  left  in  the  lung  sacs  known  as 
residual  air.  This  air  must  be  very  impure,  as  it  lacks 


64  PURE  AIR 

oxygen  and  has  much  carbon  dioxide  and  other  waste 
products  as  well.  It  is  therefore  highly  important  that 
we  force  out  as  much  of  this  air  as  possible  rather  frequently, 
and  we  can  do  this  only  by  deep  breathing.  One  of  the 
best  deep-breathing  exercises,  which  should  be  practiced 
several  times  daily  out  of  doors,  is  to  raise  the  arms  well 
from  the  sides  and  breathe  deeply  while  we  do  this,  hold 
the  breath  for  three  seconds,  exhale,  and  repeat  fifteen 
times. 

Water,  carbon  dioxide,  and  other  wastes  given  off 
through  the  lungs.  —  A  study  of  chemistry  shows  that  as 
wood,  which  contains  carbon  and  hydrogen,  combines  with 
oxygen  it  produces  two  substances,  carbon  dioxide  and 
water.  A  chemist  writes  these  two  substances  as  CO2 
(carbon  dioxide)  and  H2O  (water) .  Chemical  elements  are 
very  simple  substances  of  which  oxygen,  hydrogen,  and 
carbon  are  examples.  They  always  unite  in  definite  propor- 
tions. For  example,  water  is  always  composed  of  f  hydro- 
gen and  ^  oxygen  by  volume,  no  matter  how  much  of  it 
there  may  be.  Foods  contain  carbon,  hydrogen,  and 
oxygen,  and  when  they  are  oxidized  in  the  body,  produce  other 
substances ;  among  these  are  carbon  dioxide  and  water.  You 
are,  perhaps,  familiar  with  the  odor  that  is  noticed  when 
one  passes  from  out  of  doors  into  a  closed  room  where  sev- 
eral people  have  been  for  some  time.  The  "  stuffy  "  odor 
is  caused,  in  part  at  least,  by  certain  waste  materials  which 
have  been  passed  off  through  the  lungs  and  skin  into  the  air. 

Need  of  ventilation.  —  It  therefore  becomes  necessary 
in  rooms  where  people  are  gathered,  such  as  schoolrooms, 
churches,  "  movie  "  theaters,  and  the  rooms  of  our  own 
homes,  to  have  the  air  constantly  changed  in  order  to 
get  rid  of  the  odor,  moisture  and  carbon  dioxide,  and 


NEED  OF  VENTILATION 


to  supply  fresh  air  with  its  greater  load  of  oxygen  in 
their  place.  We  must  not  think  that  in  breathing  we  use 
all  of  the  oxygen  from  the  room.  This  would  be  impossible. 
Neither  does  the  carbon  dioxide  given  out  from  the  lungs 
make  the  air  unfit  to  breathe.  Recent  experiments  have 
shown  that  man  can  live  in 
an  atmosphere  containing 
only  ten  per  cent  oxygen,  an 
amount  so  small  that  a  match 
could  not  burn  in  it.  But 
you  are  all  familiar  with  the 
great  feeling  of  discomfort 
one  has  in  a  closed  and 
"stuffy"  room.  This  dis- 
comfort is  due  principally  to 
the  increase  in  humidity,  or 
water  content  of  the  atmos- 
phere, in  the  room.  Circu- 
lation of  the  air  will  to  a 
certain  extent  prevent  this 
discomfort.  This  circulation 
may  be  brought  about  by 
electric  fans,  blowers,  etc., 
in  large  rooms,  or  by  proper  ventilation  by  means  of 
windows  in  smaller  rooms.  On  the  other  hand,  water 
in  the  atmosphere  is  absolutely  necessary  for  health. 
In  most  artificially  heated  rooms  the  air  is  far  too  dry 
for  health,  as  people  who  live  in  such  rooms  take  cold 
more  easily  when  they  go  out  of  doors.  Air  may  be  kept 
moist  by  keeping  pans  of  water  on  the  radiators  and 
registers.  There  is  a  certain  amount  of  natural  circulation 
due  to  the  difference  in  weight  of  hot  and  cold  air. 

H.-WHIT.   CIV.  SCI.   IN  THE  HOME  —  5 


This  shows  the  direction  of  air  currents 
when  it  is  warmer  indoors  than  out. 
Can  you  account  for  this  ? 


66 


PURE  AIR 


Let  us  now  try  an  experiment  to  show  how  to  ventilate 
properly  as  a  basis  for  home  study. 

Experiment.  —  To  demonstrate  the  principles  involved  in  ventilation. 
Materials:  A  ventilation  box.     This  is  to  be  about  20  inches  tall,  2  feet 
long,  and  4  inches  thick,  having  one  of  its  large  surfaces  of  glass.     Either 
the  front  or  back  should  be  grooved  to  facilitate  opening.     A  slanting 

shelf  one  inch  wide  runs 
from  one  lower  corner 
nearly  to  the  opposite 
upper  corner.  One-inch 
holes  are  bored  in  the 
sides  and  top  as  sug- 
gested by  the  letters  A 
to  F  in  the  diagram. 
Corks  are  used  to  close 
these  holes.  Three  small 
candles  are  placed  on 
the  diagonal  shelf 
equally  spaced  so  that 
they  are  at  different 
levels. 

Method  and  Results:  (i)  Light  the  three  candles.  Close  all  the  open- 
ings. Which  candle  goes  out  first?  Explain  why.  (2)  Light  the 
candles.  Open  holes  B  and  C.  Test  currents  of  air  by  holding 
smoking  joss  stick  or  rolled  paper  at  the  openings.  Result?  (3)  Re- 
peat (2),  using  holes  A  and  D  open.  (4)  Repeat,  using  D  and  C  open. 
(5)  Repeat,  using  A  and  B  open.  (6)  Repeat,  using  E  and  F  open. 
Conclusions:  What  facts  about  circulation  of  air  are  shown  by  the  experi- 
ments? What  facts  about  changes  in  air  due  to  burning  substances? 
What  facts  are  indicated  which  will  be  helpful  in  planning  circulation 
of  air  in  our  homes?  What  conditions  found  in  the  experiment  are 
not  duplicated  in  a  room  where  we  wish  to  apply  the  principles  of 
ventilation?  In  what  particulars  can  we  apply  the  results  found  here 
to  ventilation  of  rooms  where  people  are  congregated?  Is  ventilation 
needed  for  any  other  reason  than  the  fact  that  a  part  of  the  oxygen 
of  the  air  has  been  consumed? 

Dust  and  its  dangers.  —  Not  very  many  years  ago  an 
eminent  New  York  physician  wrote  a  book  entitled  "  Dust 


A  ventilation  box. 


DUST  AND  ITS  DANGERS 


and  its  Dangers."  The  dangers,  as  he  pointed  out,  are 
not  in  the  dust  itself,  but  in  the  possible  presence  in  the 
dust  of  many  tiny  living  organisms  known  as  bacteria, 
yeasts,  or  molds.  It  is  very  easy  to  prove  the  presence  of 
these  living  plants,  for  such  they  are,  in  the  air  of  the  school- 
room. Let  us  obtain  some  previously  prepared  material 
known  as  cul- 
ture medium.1 
This  has  been 
placed  in  a  Petri 
dish,  a  small 
glass  dish  with 
a  loosely  fitting 
glass  cover.  The 
dish  and  con- 
tents have  been 
t  h  o  r  o  ug  h ly 
sterilized,  or 
rendered  free 
from  all  living 

*  Plate  culture  exposed  for  five  minutes  in  a  school  hall 

of          h  P  a  tin  &  where  pupils  were  passing  to  recitations.     Each  spot  is 

o '  a  colony  of  bacteria  or  mold. 

Thus   we    know 

that  the  culture  medium  and  everything  inside  of  the  dish  is 
dead.  If  this  dish  is  now  opened  for  five  minutes,  exposing 
the  surface  of  the  culture  medium  to  the  air  of  the  room,  then 
closed  and  put  away  in  a  warm  dark  place  for  two  or  three 
days,  a  number  of  little  dots  of  different  sizes  and  colors  will 
be  found  growing  on  the  surface  of  the  culture  medium  (see 

1  This  culture  medium  may  be  bought  already  prepared.  It  is  a  gela- 
tine or  agar-agar  preparation  upon  which  germs  grow  readily.  It  has  been 
previously  rendered  free  from  all  living  things  by  sterilization. 


68 


PURE  AIR 


illustration) .  These  little  masses  of  material  have  not  grown 
from  nothing.  They  increase  in  size  day  by  day.  They  must 
be  alive.  Since  everything  in  the  dish  was  dead,  we  have 
to  conclude  that  they  came  from  the  air.  If  we  were  to 
examine  the  material  under  a  very  high-power  microscope, 
we  would  find  it  composed  of  millions  upon  millions  of  tiny 
plant  forms  known  as  bacteria  or  m"olds.  These  tiny  plants 


DfcY  BROOM 


DAMP  BROOM 


CARPET  SWEEPER, 


VACUUM  CLEAN  CK> 


Which  of  the  above  methods  is  the  best  ?     What  evidence  is  shown  ? 

grow  and  thrive  in  our  homes  under  conditions  which  we 
shall  investigate  more  thoroughly  later. 

Proper  methods  of  sweeping  and  dusting.  —  If  these 
germs  are  present  in  dust,  then  it  is  important  for  us  to 
have  methods  of  sweeping  and  dusting  which  will  not  raise 
dust.  A  good  home  project  for  girls  and  boys  would 
be  the  working  out  of  the  best  methods  for  cleaning  their 
own  homes.  If  we  are  fortunate  enough  to  have  electricity, 
then  an  electric  vacuum  cleaner  which  sucks  up  the  dust 


HAY  FEVER 


69 


and  dirt  without  charging  the  air  with  it  is  the  best  method. 
Floors  should  be  wiped  with  a  damp  or  oily  cloth  rather 
than  swept.  Why?  An  interesting  problem  would  be 
this :  To  determine  which  method  of  cleaning  in  the 
home  is  the  most  hygienic.  Suggest  four  methods  of  clean- 
ing and  consequently  four  different  conditions  under  which 
you  could  expose  prepared  Petri  dishes  in  your  own  home. 

How  the  organs  of  respiration  are  protected  from  dust.  — 
The  nose,  the  organ  of  smell,  performs  several  other  very 
important  offices.  Just  near  its  entrance  are 
many  hairs  which  the  air  must  pass.  Down 
below,  in  the  throat  itself,  is  a  soft  lining  of 
cells  which  are  provided  with  tiny  whip-like 
structures  made  of  living  matter.  These 
structures,  called  cilia,  are  constantly  in  mo- 
tion, and  always  whip  upwards  so  as  to  ex- 
pel all  foreign  material  from  the  lungs.  The 
ciliated  cells,  together  with  the  hair  in  the 
nose,  prevent  most  foreign  matter,  such  as  dust 
and  dirt  with  their  load  of  germs,  from  going 
down  into  the  lungs.  The  lining  of  the  nose  also  moistens 
and  warms  the  air  before  it  passes  to  the  lungs. 

Hay  fever.  —  Dust,  however,  often  causes  us  trouble. 
The  disease  known  as  hay  fever  seems  to  be  caused  by  dust 
made  up  of  pollen  from  different  kinds  of  flowers.  This 
pollen  is  a  violent  poison  to  some  people,  and  causes 
sneezing,  itching  eyes  and  nose,  and  a  feeling  of  dis- 
comfort. Sometimes  relief  is  obtained  by  means  of  spray- 
ing the  air  passages,  or  plugging  the  holes  in  the  nose  with 
medicated  absorbent  cotton,  but  so  far  no  real  cure  has 
been  found  except  by  inoculation  with  various  vaccines 
made  from  the  agents  which  cause  the  trouble. 


The  tubes  lead- 
ing into  the 
lungs  are  pro- 
tected from 
dust  by  means 
of  ciliated 
cells. 


PURE  AIR 


AcLe-noicl 
Growth.3 


Diseases  of  the  air  passages.  —  We  are  probably  more 
aware  of  diseases  of  the  air  passages  than  almost  any  other 
part  of  the  body.  Nearly  everybody  has  a  cold  at  one 
time  or  another,  and  we  have  all  heard  of  and  perhaps 
suffered  from  ravages  of  influenza  and  pneumonia.  Other 
diseases  which  unfortunately  attack  the  air  passages  are 
diphtheria,  tonsillitis,  laryngitis,  pharyngitis,  bronchitis, 

catarrh,      croup,       and 
whooping  cough. 

Adenoids  and  tonsils. 
Tonsils  often  make 
much  trouble  for  us. 
Germs  lodge  and  grow 
in  them  and  cause  many 
diseases.  Infected  ton- 
sils should  be  removed. 
Polyps  are  soft  jellylike 
growths  in  the  nose 
which  cause  stuffiness, 
difficulty  in  breathing, 
and  thickness  of  voice 
in  children.  If  present, 
they  should  be  removed 
by  a  physician,  as  the 
loss  of  the  sense  of  smell,  as  well  as  much  discomfort,  may  fol- 
low. Adenoids  are  almost  always  accompanied  by  breathing 
through  the  mouth,  snoring  at  night,  and  general  listlessness 
and  indifference  to  work  and  play.  Adenoids  grow  in  the 
back  part  of  the  nose,  and  shut  off  the  air  supply  through  this 
organ.  They  should  be  treated,  or  removed  if  very  large. 

Artificial  respiration.  —  Accidents  which  shut  off  the 
supply  of  oxygen,  are  drowning,  suffocation  from  gas, 


Section  of  head  and  neck  showing  position  of 
adenoids  and  tonsils. 


ARTIFICIAL  RESPIRATION 


71 


stoppage  of  the  nose  or  throat,  and  electric  shock.  In 
case  of  any  accident  in  which  breathing  stops,  it  is  neces- 
sary to  work  quickly.  Send  for  a  doctor  at  once.  The 
person  should  be  taken  into  the  open  air  if  possible,  the 
clothes  loosened,  and  artificial  respiration  started  as  soon  as 
possible.  In  the  case  of  drowning,  the  first  thing  to  do  is  to 
get  the  water  out  of  the  lungs  and  air  passages.  -  To  do  this 
we  must  raise  the 
lower  part  of  the 
body  of  the  patient 
from  the  ground  so 
that  the  water  may 
run  out.  Lift  the 
patient  up  quickly 
two  or  three  times 
with  a  jerk,  with  the 
arms  underneath  the 
abdomen.  Do  not 
take  more  than  half 
a  minute  to  do  this. 
Water  from  the 
lungs  will  thus  be 
forced  out.  Then 
at  once  place  the  patient  on  the  ground  face  down,  arms 
outstretched,  and  with  head  on  one  side  so  that  air  can 
get  in  through  the  nose  and  mouth.  Place  yourself 
astride  of  the  patient,  but  without  resting  any  weight 
on  him.  Place  the  palms  of  your  hands  across  the 
small  of  his  back,  thumbs  touching.  Then  allow  your 
weight  to  fall  on  your  wrists  by  bending  your  body  for- 
ward. This  decreases  the  size  of  the  patient's  chest  cavity 
and  forces  air  out  of  his  lungs.  Now  release  the  pressure 


Shaefer  method  of  artificial  respiration. 


72  PURE   AIR 

by  swinging  backward  quickly.  The  elastic  chest  of  the 
patient  will  go  back  to  its  original  position,  thus  drawing 
air  into  the  lungs.  Perform  these  motions  about  fourteen 
or  fifteen  times  a  minute,  and  keep  it  up  for  several  hours, 
if  necessary,  for*  victims  of  drowning  accidents  have  been 
brought  back  to  life  after  hours  of  patient  work.  If  there 
are  others  to  help  have  them  rub  the  arms  and  legs  toward 
the  body,  as  this  helps  the  circulation,  and  as  soon  as  possi- 
ble cover  with  warm  blankets.  As  the  patient  gets  better, 
give  him  warm  drinks  and  place  hot  water  bags  at  the  hands 
and  feet.  Keep  a  crowd  away  from  the  patient,  as  he  needs 
all  the  air  he  can  get. 

In  case  of  suffocation,  where  the  patient  has  lost  con- 
sciousness, start  artificial  respiration  as  directed  above,  and 
send  at  once  for  a  doctor.  In  case  of  electric  shock  the 
patient  must  first  be  rescued.  Remember  that  live  wires 
transfer  their  electricity  through  the  body  of  the  victim. 
It  is  necessary  to  stand  on  dry  wood,  cloth,  or  rubber,  and 
then  you  should  not  touch  the  person  you  are  rescuing  with 
your  hands.  You  may  be  able  to  remove  the  wire  with 
a  dry  piece  of  wood,  or  cut  it  with  an  ax  having  a  dry 
wooden  handle.  If  the  vie  tun  lies  on  the  wire,  place  coats 
under  his  head  and  feet  and  lift  him  off.  As  soon  as  you 
have  rescued  the  victim  start  artificial  respiration  at  once, 
for  time  is  a  very  important  factor  here,  especially  if  he 
has  become  unconscious.  Treatment  for  lightning  shock  is 
the  same  as  for  electric  shock. 

Fainting.  —  A  fainting  attack  is  brought  on  by  a  de- 
crease in  the  amount  of  blood  in  the  brain.  A  person 
feeling  dizzy  should  lie  down  with  the  head  lower  than 
the  body.  This  will  usually  prevent  fainting  and  will 
hasten  the  return  to  consciousness  of  one  who  has 


REFERENCE  BOOKS 


73 


fainted.  Abundant  fresh  air  and  loose  clothing  are  helps. 
Enforced  respiration  often  shortens  an  attack.  Respi- 
ration may  be 
stimulated  by 
throwing  cold 
water  upon  the 
face  and  chest. 
Ammonia  may 
also  be  inhaled, 
but  avoid  letting 
any  drop  into 
the  eye  or  irri- 
tating the  air 
passages  unduly 
by  holding  it  too 
near  the  mouth 


or  nose. 


Why  is  the  head  lower  than  the  rest  of  the  body  ? 
(After  Tolman.) 


REFERENCE  BOOKS 

Allen,  Civics  and  Health,  Chapters  V,  VI  (For  teacher).     Ginn  and  Company. 

—  American  Red  Cross  Textbook  on  First  Aid.    Blakiston's  Son  and  Company. 
Broadhurst,  Home  and  Community  Hygiene,  Chapters  IX,  XI   (Teacher's  use). 

J.  B.  Lippincott  Company. 

Chapin,  Sources  and  Modes  of  Infection  (Teacher's  use).     J.  B.  Lippincott  Company. 
Fisher  and  Fisk,  How  to  Live,  Chapter  I  (Advanced  readers).     Funk  and  Wagnalls 

Company 
Hill,  The  New  Public  Health,  Chapters  III,  IX,  XV  (Teacher's  use).    The  Mac- 

millan  Company. 

Hough  and  Sedgwick,  The  Human  Mechanism.     Ginn  and  Company. 
Hunter,  A  Civic  Biology,  Chapters  XXI,  XXII.     American  Book  Company. 
Hunter,  Laboratory  Problems  in  Civic  Biology.     American  Book  Company. 
Lee,  Health  and  Disease,  Chapters  VIII,  XII  (Teacher's  use).     Little,  Brown,  and 

Company. 

New  York  State  Ventilation  Commission  Reports  (Advanced  readers). 

Prudden,  Dust  and  Its  Dangers.     G.  P.  Putnam's  Sons. 

Ritchie,  Primer  of  Sanitation,  Chapters  XX,  XXI.     World  Book  Company. 

Woods  Hutchinson,  Preventable  Diseases.     Houghton  Mifflin  Company. 


CHAPTER   V 
WATER  IN   THE   HOME 

Problems.  —  i.  To  understand  the  cycle  of  water  in 
nature. 

2.  What  are  the  available  sources  of  a  home  water  supply? 

3.  How  can  you  tell  safe  from  unsafe  water? 

4.  How  can  water  be  brought  into  the  home  ? 

5.  What  is  a  "solution"? 

Experiments. —  i.   To  find  a  method  of  purifying  water  (distillation). 
2.   To  determine  how  air  pressure  can  lift  water. 

Project  I.  —  To  MAKE  A  LIFT  PUMP. 

Plan  how  you  can  make  a  working  model  of  a  lift  pump  or  a  force 
pump. 

Suggestions.  —  Large  glass  tubing  and  cylindrical  lamp  or  gas 
chimneys  make  good  pump  barrels.  Valves  are  easily  made  by 
using  sheet  rubber  with  a  long  tack  or  pin  passing  through  it. 

Your  report  should  contain  at  least  two  good  diagrams  showing 
your  pump  model  in  action. 

Project  n.  —  How  MUCH  WATER  is  WASTED  BY  DRIPPING  FAUCETS? 

Devise  a  method  to  find  out  how  much  water  is  lost  from  a  leaky 
faucet.  How  much  could  be  lost  in  a  year? 

If  the  water  is  metered,  what  is  its  cost? 

What  would  be  the  difference  in  gallons  lost  or  in  money  value 
per  year  in  the  following  instances? 

1.  When  the  leak  is  drop  by  drop. 

2.  When  the  smallest  possible  stream  is  running. 

74 


PURE  WATER 


75 


Let  your  report  include  all  details  of  your  processes,  and  also  a 
report  on  the  results  of  any  attempts  to  stop  the  loss. 

What  if  similar  leaks  occurred  in  half  the  faucets  in  town? 

Pure  water.  —  What  is  pure  water  ?  We  have  already 
seen  water  condensed  as  a  product  of  a  burning  candle, 
and  in  a  future  chapter  we  shall  see  that  it  is  the  product 
of  burning  hydrogen  in  oxygen.  It  is,  then,  a  compound 
produced  by  the  combination  of  the  chemical  elements,  oxy- 
gen and  hydrogen.  All  pure  water  contains  hydrogen  and 
oxygen  and  nothing  else.  When  other  substances  are  mixed 
with  water  there  are  certain  methods  by  which  pure  water 
may  be  separated  from  some  or  all  of  the  impurities.  One 
purifying  process  is  distillation.  Let  us  see  if  this  gives 
us  pure  water  from  impure  water. 


Experiment.  —  To  find  a  method  of  purifying  water. 

Materials:   Two  500  cc.  flasks.     A  one-hole  rubber  stopper.     Glass  tube. 

Ring  stand. 
Method:   Prepare  a  sample  of  impure  water  by  adding  a  teaspoonful  of 

salt  and  an  equal  amount  of  clay  or  fine  sand,  and  a  few  crystals  of 

potassium  permanganate  to  a  half  pint 

of   water.     Fill  one  flask  about  half 

full  of  the  prepared  water  and  place 

on  ring  stand.     Arrange  to  carry  the 

steam  through  a  bent  glass  tube  into 

the  other  flask  which  stands  under  a 

stream  of  cold  water.     Heat  the  flask 

which  is  supported  on  a  ring  stand. 

When  an  inch  depth  of  distilled  water 

has  been  prepared  remove  the  heat. 
Results  and  Conclusion:    How  does  the 

distilled    water     compare    with    the 

original   in    appearance?     In    taste? 

What  can  you  say  regarding  distillation  as  a  method  for  purifying 

water?     Are  any  of  the  impurities  left  in  it?     Explain  fully  the  pro- 
cess of  distillation. . 


Distillation  apparatus. 


76 


WATER  IN  THE  HOME 


Rain  water.  —  When  we  think  it  out  rain  water  must 
also  be  very  pure,  for  is  it  not  condensed  in  somewhat  the 
same  way  as  the  drops  of  water  we  collected  in  the  last- 
experiment?  Breathe  on  a  cool  glass.  What  happens? 
The  little  drops  of  moisture  have  been  condensed  because 
warm,  moist  air  was  suddenly  cooled.  Moisture  in  the 
air  comes  from  evaporation  from  water  surfaces  and  from 
all  moist  surfaces.  Leaves  give  off  moisture  in  the  form  of 

water  vapor.  An  acre  of 
clover  may  give  off  from 
500  to  750  tons  of  water 
during  a  single  season. 
The  production  of  one 
pound  of  some  plant 
foods  requires  that  two 
to  five  tons  of  water  be 
taken  from  the  soil  and 
most  of  this  is  evapo- 
rated into  the  air  from 
the  leaves.  An  acre  of 
Indian  corn  gives  off 
nearly  a  thousand  tons  of  water  in  a  season.  When  this 
moisture  in  the  air  condenses  clouds  form.  From  clouds 
water  falls  in  the  form  of  rain. 

How  we  get  rain  water.  —  In  many  parts  of  the  world 
people  drink  rain  water.  On  the  islands  of  Bermuda,  for 
example,  great  cisterns  are  cut  in  solid  rock  to  hold  the 
water,  and  the  people  of  the  islands  depend  entirely  upon  this 
supply.  If  rain  water  is  collected  in  clean  cisterns  or  bar- 
rels it  is  perfectly  pure.  But  unfortunately  the  cisterns 
and  rain  barrels  are  sometimes  not  clean.  Roof  drains  and 
gutters  are  allowed  to  become  clogged  with  decaying  vege- 


Explain  this  diagram. 


SPRINGS  AND  WELLS 


77 


table  matter  or  sometimes  a  poor  quality  of  paint  used  on 
the  roofs  will  come  off  in  the  water.     All  of  these  things 


Diagram  to  show  the  relation  of  springs  and  wells  to  underground  water. 

cause  rain  water  to  become  unfit  for  drinking  purposes. 
An  excellent  plan  is  to  have  the  first  water  which  falls  run 
off  without  entering  the  barrel  or  cistern,  because  that 
water  is  almost  sure  to  contain  dust  and  other  impurities. 
The  best  type  of  cistern  is  a  tank  of  non-porous  material 
placed  in  the  ground. 

Springs  and  wells.  —  Any  boy  or  girl  who  has  lived  in 
the  country  knows  what  a  spring  is  and  any  one  with  a 
little  thought  can  see  how  a  spring  might  arise  from  rain 
water.  The  rain  soaks  into  the  ground  until  it  comes  to 
a  layer  through  which  it  cannot  pass  (impervious  layer). 
It  then  seeps  along  until  it  acquires  pressure  enough  to 
flow  out.  If  the  saturated  zone  rises  to  the  surface  a 
spring  may  result.  A  glance  at  the  accompanying  diagram 
will  show  how  springs  occur.  In  a  gushing  spring  the  water 
is  forced  out  under  pressure.  Water  which  has  soaked  into 
the  ground  at  some  point  far  distant,  often  travels  under- 
ground between  two  layers  of  impervious  material,  follow- 
ing along  some  layer  of  soil  or  rock  which  allows  its  passage, 
and  finally  finds  its  way  to  the  surface  through  some  crack 
or  hole  in  the  hard  rock.  Artesian  wells  are  made  when 


WATER   IN  THE  HOME 


such  underground  water  sources  have  been  tapped  artifi- 
cially. Sometimes  this  water  may  run  underground  for  a 
long  distance,  and  come  from  a  much  higher  altitude,  so 
that  when  it  is  tapped  it  shoots  into  the  air  to  some  height. 
What  is  impure  water?  —  We  usually  consider  water 
pure  unless  it  contains  something  that  is  injurious  to  health. 
Ordinary  dirt  or  mud  found  in  water  will  not  cause  illness 
unless  there  is  decaying  organic  matter  in  it.  Wherever 
we  find  decay,  we  find  germs  which  cause  this  decay,  so 
impure  water,  from  a  health  standpoint,  is  water  containing 
germs.  When  we  realize  that  germs  of  different  kinds 
exist  in  the  food  tube  of  our  body,  and  that  the  wastes 
which  are  passed  off  are  full  of  germs,  then  it  is  evident 
that  water  which  contains  sewage  is  impure.  Any  water 

drawn  from  the  sur- 
face of  the  land 
would  be  more  likely 
to  contain  such 
wastes,  and  hence 
would  be  more  dan- 
gerous than  water 
coming  from  under- 
ground. 

Safe  wells  and 
deadly  ones.  - 
Many  of  us  who 
have  visited  the 
country  on  our  vaca- 
tions remember  with  pleasure  the  cold  water  from  the  deep 
well  or  hillside  springs  near  the  farm  house.  Look  at  the 
picture  and  see  how  a  spring  may  be  polluted  by  a  cess- 
pool. We  have  all  doubtless  seen  places  where  the  well 


A  spring  located  like  this  one  is  deadly.     Are  there 
any  such  in  your  locality? 


HOW  WE  GET  WATER  INTO  OUR  HOUSES 


79 


water  might  be  a  source  of  danger,  for  all  the  wastes  from 
the  house  sinks,  from  the  barnyard,  and  from  the  privy 
or  cesspool  might  soak  into  the  well  and  render  it  im- 
pure. Could  you  really  determine  a  safe  place  for  a  well 
without  knowing 
something  of  the 
rock  and  soil  under 
the  house  and 
grounds?  Drainage 
from  the  soil  may 
mean  that  impuri- 
ties reach  the  well. 
We  must  also  pro- 
tect the  well  from 
the  surface  drainage. 
Study  the  picture 
of  the  two  wells 
shown  here,  and  explain  why  the  building  of  a  con- 
crete parapet  which  slopes  away  from  the  opening  of  the 
well  will  protect  the  water  in  the  well.  In  addition  to 
surface  protection,  we  should  know  how  the  land  drains 
so  as  to  be  sure  that  the  well  is  safe.  If  one  is  uncertain 
as  to  the  purity  of  the  water,  a  sample  can  be  sent  to  the 
town  or  state  bacteriologist,  to  determine  whether  the 
water  is  safe  to  drink.  This  should  be  done  in  any  case 
where  you  suspect  that  the  water  is  not  pure.  A  driven 
well  on  a  slight  elevation,  when  the  pipe  is  driven  deep  into 
the  soil  and  situated  at  least  100  feet  from  a  cesspool,  or 
barnyard,  will  in  ordinary  sandy  soil  give  pure  water. 
This  makes  a  particularly  safe  well. 

How  we  get  water  into  our  houses.  —  This  is  a  problem 
that  the  city  dweller  does  not  think  much  about,  because 


Would  you  choose  your  water  supply  from  A  or  from  B  ? 


8o 


WATER   IN  THE   HOME 


water  is  delivered  directly  to  his  home  through  pipes.  The 
problem  of  city  water  supply  will  be  taken  up  later.  It  is 
sometimes  quite  easy  for  the  country  house  to  have  running 
water  simply  because  water  is  pulled  down  by  gravity,  or 
"  runs  down  hill."  If  the  spring  or  source  from  which  the 
water  is  taken  is  above  the  height  of  the  house,  it  can  be 
piped  into  the  house  easily ;  if  the  well  or  spring  is  below 
the  house  we  have  a  different  problem. 

If  the  country  boy  or  girl  acquires  a  little  knowledge  of 
air  pressure,  it  might  enable  him  or  her  to  plan  how  to 

make  use  of  this  knowledge  to 
deliver  water  into  the  house. 
We  have  already  seen  that  air 
has  weight.  If  you  take  a 
tumbler  of  water,  place  a 
smooth  card  over  the  tumbler 
and  then  invert  it  carefully, 
you  can  lift  the  glass  upside 
down  with  the  water  in  it. 
A  moment's  thought  will  tell 
you  that  something  is  pressing 
upward  on  the  card,  or  that 
the  air  pressing  against  the 
card  weighs  more  than  the 
water  held  in  the  glass.  If  you  take  a  wide-mouthed  bottle, 
fill  it  with  water,  insert  a  cork  containing  a  glass  tube,  and 
then  try  to  suck  the  water  out  you  will  be  unable  to  do  so. 
Loosen  the  cork  a  little  and  then  try,  and  you  will  find  that 
you  can  suck  the  water  out.  We  may  demonstrate  this 
same  principle  in  another  way. 

Experiment.  —  To  show  how  air  pressure  can  lift  water. 

Materials:  A  U-tube,  piston,  and  stopper  to  fit,  a  glass  tube. 


The  water  is  held  in  the  glass  by  the 
upward  pressure  of  the  air. 


HOW  WE  GET  WATER  INTO  OUR  HOUSES         81 

Method  and  Results:  (a)  Fill  the  U-tube  with  water.  Push  the  piston 
three  fourths  of  the  way  down  one  side  of  the  U-tube.  Place  the 
stopper  in  the  other  end,  making  sure  that  it  is  air-tight.  Pull  the 
piston  to  the  top  of 
the  tube.  Result? 
(b)  Repeat  (a)  and 
leave  the  end  of  the 
tube  open.  Result? 

Conclusion :  Explain 
why  the  water  fol- 
lows the  piston  to  a 
higher  level  in  one 
case  than  in  the 
other. 

Application:  If  the 
tube  were  straight  and  dipped  into  a  jar  of  water,  would  the  water 
follow  the  piston?  Explain.  Explain  how  one  can  drink  soda  water 
through  a  straw. 

Let  us  apply  this  principle  to  the  pump.     If  the  tube 
is  placed  in  the  water  as  in  the  diagram  and  we  suck  on 

the  tube,  we  can  pull 
the  water  up.  This 
is  because  we  have 
removed  the  pres- 
sure of  the  air  in 
the  tube  and  this  al- 
lows the  air  outside 
the  tube  to  force  the 
water  up  the  tube. 
If  we  now  substi- 
tute for  the  tube  the 
The  lift  pump.  pump,  consisting  of 

a  piston  (see  diagram)  containing  a  lifting  valve,  we  see 
that  when  this  piston  is  raised  the  water  is  pushed  into  the 
tube  by  the  weight  of  the  air  pressing  down  on  the  water 

H.-WHIT.   CIV.   SCI.   IN  THE   HOME  —  6 


82 


WATER   IN  THE   HOME 


in  the  cistern.  When  the  piston  is  lowered  the  valve  in 
the  piston  opens,  thus  allowing  the  water  to  run  into  the 
space  above  the  piston.  On  the  next  upward  stroke  of 
the  piston  this  water  which  is  held  above  is  lifted  still 
higher  in  the  tube  until  eventually 
it  flows  out  of  the  pump.  This 
pump,  known  as  the  lift  pump,  will 
only  raise  water  to  a  height  of 
about  33  feet  because  the  weight 
of  the  air,  which  presses  down  with 
a  force  of  fifteen  pounds  to  the 
square  inch  upon  the  surface  of  the 
water  in  the  cistern,  can  balance  a 
column  of  water  only  33  feet  high. 
In  practice  the  lift  pump  will  rarely 
lift  water  more  than  28  feet  because 
of  leakage  around  the  piston  and 
valves. 

If  we  wish  to  force  water  above 
twenty-eight  feet  we  use  a  force 
pump.  This  is  illustrated  in  the 
accompanying  diagram.  Study  it 
carefully  and  explain  why  we  are 
able  to  raise  water  higher  by  this  method  than  by  the  lift 
pump.  Chamber  A  holds  air  which  may  be  compressed 
in  order  to  give  a  continuous  flow  of  water.  Can  you  ex- 
plain how  it  does  this? 

The  pneumatic  tank  system.  —  In  some  houses  a  supply 
system  by  which  water  can  be  piped  and  sent  to  all  parts 
of  the  house  is  used.  This  can  be  done  through  the  use  of 
a  pneumatic  tank.  (See  illustration  on  page  83.)  Water  is 
forced  into  the  tank  and  the  confined  air  above  it  is  com- 


The  force  pump. 


THE  PNEUMATIC   TANK  SYSTEM  83 

pressed  so  that  it  exerts  great  lifting  power.  Thus  when 
the  tank  is  three  fourths  full  of  water  the  air  is  compressed 
to  one  fourth  of  its  original  volume  and  the  pressure 
becomes  four  times  that  of  the  atmosphere,  or  four  atmos- 


Pneumatic  tank  system  of  distribution  of  water. 

pheres.     Such  a  pressure  will  easily  force  water  higher  than 
the  top  of  an  ordinary  house. 

Experiment.  —  To  demonstrate  the  use  of  the  pneumatic  tank. 

Materials:  An  eight-ounce,  wide-mouth  bottle.  Two-hole  rubber  stop- 
per. Glass  tubes.  Force  pump.  Ring  stand.  Rubber  tubing. 

Method:  Invert  the  bottle  and  support  it  on  the  ring  stand.  Make  a  U 
bend  at  one  end  of  a  four-foot  glass  tubing.  Insert  this  in  the  rubber 


84 


WATER   IN  THE  HOME 


stopper.  One  end  of  the 
other  glass  tube  is  con- 
nected by  a  rubber  tub- 
ing to  the  outlet  valve  of 
the  force  pump.  The  in- 
let valve  of  the  pump  is 
connected  by  a  rubber 
tubing  to  a  jar  of  water. 
Wire  the  stopper  securely 
in  the  mouth  of  the  bottle. 
Pump  water  into  the  bot- 
tle, and  as  it  presses  the 
air,  note  how  high  it  rises 
in  the  glass  tube.  Connect 
another  four-foot  length  of 
glass  tubing  on  top  of  the 
first  one.  When  the  water 
fills  one  fourth  of  the  bot- 
tle, what  is  the  height  of 
the  water  in  the  tube  ? 

Application:  Apply  this 
principle  to  a  house  sup- 
ply.    How  high  could  the 
water    be    raised    if    the 
air  in  the  bottle  were  compressed  to  half  its  original  volume  ? 

Faucets.  —  Any  water  system  in  the  house  means  that 
we    must    have 
pipes  that  carry 
the  supply  from 
where  the  water 
enters  the  house 
to   the   kitchen, 
to    the   laundry 
tubs,    to 
bathroom 


the 
and 

toilets.  A  cut-off 
valve   is  placed 


Two  types  of  faucets:  screw  and  spring. 


HOW  TO  STOP  FAUCETS  FROM  DRIPPING 


close  to  the  point  where  the  water  enters  the  house. 
Why  ?  In  order  to  obtain  water  when  we  wish  it  a  device 
called  the  faucet  is  necessary.  A  careful  study  of  the  two 
diagrams  will  sh®w  how  these  devices  are  operated.  The 
type  most  in  use  is  known  as  the  screw  faucet.  In  this 
type,  as  the  handle  is  screwed  down,  a  washer,  which  may  be 
a  round  perforated  disc  of  rubber,  is  forced  down  over  the 
opening  where  the  water  flows,  thus  making  it  water-tight. 
In  another  common  type  of  faucet,  the  pressure  of  a  spring 
(see  diagram)  holds  the"  washer  down  so  that  no  water  can 


Water  waste  per  year. 

get  out.     When  we  squeeze  the  handles  together,  this  pres- 
sure is  released  and  the  water  flows  through. 

How  to  stop  faucets  from  dripping.  —  Any  handy  boy, 
or  girl  either,  for  that  matter,  should  know  how  to  stop 
faucets  from  dripping.  The  first  thing  to  do  is  to  turn 
off  the  supply  of  water  at  the  cut-off  in  the  cellar, 
then  with  your  wrench  take  off  the  handle  of  the  faucet 
and  remove  the  washer.  You  will  probably  find  the  washer 
either  broken  or  badly  worn.  A  new  washer  which  can  be 
procured  at  any  hardware  store  should  then  be  inserted  and 
the  handle  replaced.  Sometimes  a  faucet  when  turned  on 
gives  an  annoying  noise,  due  to  vibration  as  the  water 
passes  through.  If  caused  by  a  loose  washer  it  is  easily 
remedied.  Leaky  faucets  waste  money ;  do  not  allow 
any  of  them  in  your  home. 


86 


WATER  IN  THE  HOME 


What  we  mean  by  solution.  —  You  are  all  aware  of  the 
fact  that  sugar  placed  in  your  lemonade  soon  dissolves  in 
it  and  disappears,  but  you  can  taste  the  sugar  in  all  parts 
of  the  glass  of  lemonade.  If  you  were  to  allow  crystals 
of  eosin  (the  material  from  which  red  ink  is  made)  to  dis- 
solve in  a  bowl  of  water,  in  a  short  time  the  eosin  would 
have  passed  to  all  parts  of  the  water,  giving  it  a  uniform 
pink  color. 

When  a  substance  completely  dissolves  in  a  liquid  so  as 
to  become  permanently  a  part  of  it,  we  say  the  substance 

is  soluble  in  water, 
and  that  we  have 
a  solution.  Water 
takes  up  mineral 
matter  in  solution. 
Rain  water,  al- 
though perfectly 

Formation  of  caves  by  water  running  through  lime-      pure  as  it  drODS  from 

the  clouds,  after 

soaking  into  the  ground  may  soon  take  up  into  itself  mineral 
matter  by  solution.  Certain  minerals,  particularly  com- 
pounds of  calcium  (lime)  and  magnesium,  are  slightly  soluble 
in  ground  water,  and  indeed  in  some  parts  of  the  country, 
great  gaps  and  caves  have  been  formed  by  water  gradually 
running  through  limestone  and  dissolving  it  out.  We 
must  not  confuse  solutions  with  muddy  water,  for  if  we 
allow  a  glass  of  muddy  water  to  stand,  the  mud  eventually 
settles  to  the  bottom,  or  if  the  water  is  passed  through  filter 
paper,  it  remains  on  the  filter ;  but  when  mineral  substances 
are  in  solution,  they  pass  through  the  filter  with  the  water. 
Hard  and  soft  water.  —  Water  that  has  taken  up  a  con- 
siderable amount  of  soluble  mineral  material  is  called  hard 


HOW  WE   MAY   MAKE  WATER  PURE 


water,  while  rain  water  and  other  waters  that  have  little 
or  no  dissolved  mineral  matter  in  them  are  known  as 
soft  waters.  We  can  usually  tell  hard  water  because  soap 
does  not  readily  make  a  good  lather,  or  suds,  with  it.  We 
find  that  the  soap  comes  to  the  top  in  a  sticky,  insoluble 
scum.  Hard  water  leaves  a  deposit  in  kettles,  feels  harsh 
to  the  hands,  and  requires  much 
wrashing  powder,  else  it  is  very 
wasteful  of  soap.  Such  waters 
are  perfectly  good  to  drink,  but 
must  be  treated  with  chemicals 
before  using  them  for  washing 
purposes.  Washing  soda  added 
to  the  water  before  soap  is  used 
will  usually  make  the  water  bet- 
ter suited  for  washing. 

How  we  may  make  water 
pure.  —  We  have  already  seen 
that  harmful  water  contains 
germs.  Germs  are  living  organ-  Notice  the  bubbles  of  air  which  es- 

.  ,  fit  cape  when  water  is  first  heated. 

ISmS,      and     many     Of     them     do          Why  is  boiling  water  sometimes 

recommended?      . 

harm  when  they  are  alive.    Any 

method  which  will  kill  them  and  will  not  harm  the  water 
will  therefore  render  it  safe  to  drink.  Boiling  water  for  a 
period  of  at  least  ten  minutes  will  kill  practically  all  harmful 
germs,  so  that  we  may-  safely  drink  such  water.  Unfortu- 
nately, boiled  water  has  a  flat  and  unpleasant  taste,  due  to  the 
fact  that  the  air  which  was  held  in  solution  has  been  forced 
out  of  it.  In  order  to  make  such  water  palatable  we  may 
shake  it  up  in  a  bottle  half  full  of  air  or  allow  it  to  stand 
exposed  to  the  air.  Such  water  dissolves  some  of  the  air 
and  again  assumes  its  palatable  taste,  and  is  good  to  drink. 


88 


WATER   IN   THE   HOME 


SCORE  CARD.    WATER  IN  MY  HOME 


EXCELLENT 

FAIR 

VERY  POOR 

MY 

SCORE 
Total 

A   SAFE 
WATER 
SUPPLY 

Water  protected 
f  r  om         surface 
drainage     (deep) 

(s) 

Water  without  sedi- 
ment (i) 
Water    having    no 
color  (i) 
Water    having    no 
odor    (indication 
of    organic   mat- 
ter) (2) 
Use  of  bottled  wa- 
ter  for   drinking 
(i) 

Water  from  shallow 
source    protected 
against      surface 
drainage  (3) 
Water  having  some 
sediment  (5) 
Water  having  slight 
color  (|) 
Water  having  slight 
odor  (i) 

Boiled     water     for 
drinking  (i) 

No  protection  from 
drainage.      Cess- 
pool     or      privy 
within  100  ft.  (o) 
Much  sediment  (o) 

Much  color  (o) 
Much  odor  (o) 

Neither  boiled  nor 
bottled     water 
used  for  drinking 
(o)      " 

AMPLE 
WATER 
SUPPLY 

Always  enough  wa- 
ter   for    all    pur- 
poses at  all  sea- 
sons       including 
possible  fire  (5) 
Head  of  water  suf- 
ficient   to    throw 
stream        over 
house  (5) 

Supply  only  to  two 
lower     floors     of 
home  (3) 

Supply     sometimes 
low  in  hot  sum- 
mer or  cold  win- 
ter (3) 

Supply  only  to  low- 
est floor  of  house 
(2) 

Supply  usually  low 
in  winter  or  sum- 
mer (i) 

ALL  PARTS 
SUPPLIED 
WITH  PIP- 
ING AND 
FIXTURES 

Water  supplied  un- 
der   pressure    to 
bathroom     (i), 
toilet     (2),    sink 
(i),     and     tubs 
in      kitchen      or 
laundry  (i) 
No  pumps  :  gravity 
system:  piped  to 
all   parts  of   the 
house  (<;) 

Water  supplied  un- 
der pressure  from 
pneumatic     tank 
to  bathroom  (i), 
toilet     (2),    sink 
(i),  tubs  (i) 

Pumps:     no   pneu- 
matic tank.   Wra- 
ter  supplied  only 
to  sink  (i),  tubs 
(i) 

.... 

.... 

CONDI- 
TION OF 
PLUMBING 

Pipes  in  good  con- 
dition;   no  leaks 
(2) 
Faucets    all    tight; 
no   dripping    (2) 
Pipes  never  freeze 

(2) 

Plumbing     all     ex- 
posed (2) 
No  odors  (2) 

Pipes  in  fair  condi- 
tion ;    sometimes 
leak  (i) 
Faucets     drip     at 
times  (i) 
Pipes  freeze  in  very 
cold  weather  (i) 

Plumbing  partly  ex- 
posed (i) 
Slight  odor  at  times 
(i) 

Pipes  old  and  leaky 
(o) 

Faucets  constantly 
drip  (o) 
Pipes  freeze  in  or- 
dinary winter 
weather  (o) 
No  exposed  plumb- 
ing (o) 
Much     odor     from 
plumbing  (o) 

SOFT 
WATER 
PROVIDED 

Water  is  soft  (4) 

Rain  water  and  ce- 
ment cistern  (3) 

Bucket     pump     or 
other    means    of 
mixing    air    with 
water  (2) 
Flow-off     of     first 
rain   water   from 
roof  (i) 

Water  of    medium 
hardness  (2) 
Rain  water  in  tight- 
ly covered  barrel 
(i)     ' 
Water    falls    from 
height  into  barrel 
thus    mixing    air 
with,  it  (i) 
Roof  clean,  water- 
proof paint  (i) 

Water    very    hard 
(o) 
Rain      barrel      ex- 
posed,   no    tight 
cover  (o) 
No  method  of  mix- 
ing air  in  water 
(o) 

Water  smells  or  is 
dirty  (o) 

.... 

GRAND   TOTAL 

SCORING  MY  HOME  WATER  SUPPLY  89 

Scoring  my  home  water  supply.  —  Any  boy  or  girl  who 
has  read  this  chapter  with  thought  now  realizes  the  impor- 
tance of  our  water  supply  and  how  great  an  advantage 
those  of  us  who  live  in  cities  have  over  those  who  have 
no  safe  supply  or  to  whom  it  is  not  delivered  in  pipes. 
The  score  on  the  preceding  page  will  probably  be  much 
higher  for  those  who  live  in  the  city. 

REFERENCE   BOOKS 

Barber,  General  Science,  Chapter  IX.     Henry  Holt  and  Company. 

Broadhurst,  Home  and  Community  Hygiene,  Chapter  V.     J.  B.  Lippincott  Company. 

Butler,  Household  Physics.     Whitcomb  and  Barrows. 

Caldwell  and  Eikenberry,  General  Science,  Chapter  IX.     Ginn  and  Company. 

Clark,  Introduction  to  Science,  Chapter  XXXIV.     American  Book  Company. 

Hazen,  Clean  Water  and  How  to  Get  It  (Teacher's  use).     John  Wiley  and  Sons. 

Hoadley,  Essentials  of  Physics.     American  Book  Company. 

Hunter,  A  Civic  Biology,  Chapter  VI.     American  Book  Company. 

Lynde,  Physics  of  the  Household.     The  Macmillan  Company. 

Ritchie,  Primer  of  Sanitation,  Chapter  XX.     World  Book  Company. 

Smith  and  Jewett,  Introduction  to  the  Study  of  Science,  Chapter  V.     The  Macmillan 

Company. 

Yearbook,  U.  S.  Dept.  Agri.,  Clean  Water  and  How  to  Get  It  on  the  Farm. 
Weed,  Chemistry  in  the  Home,  Chapter  III.     The  American  Book  Company. 


CHAPTER  VI 
THE  USES   OF  FOODS 

Problems.  —  i.    To  learn  the  uses  of  foods. 

2.  To  learn  of  what  our  bodies  are  made  and  what  must 
be  supplied  if  we  are  to  grow. 

3.  To  learn  to  tell  what  different  nutrients  foods  contain. 

4.  To  learn  how  and  where  food  is  made  ready  for  ab- 
sorption. 

5.  To  determine  reasons  for  differences  in  diets. 

6.  How  to  select  a  proper  and  economical  variety  of  food. 

7.  How  and  why  foods  should  be  cooked. 

Experiments. —  i.   To  show  the  presence  of  carbon  and  water  in  foods. 

2.  To  make  tests  for  the  carbohydrate  foods,  sugar  and  starch. 

3.  A  test  for  protein. 

4.  A  test  for  fat  or  oil. 

5.  To  show  digestion  of  starch  with  saliva. 

Project  I.  —  WHAT  NUTRIENTS  ARE  IN  THE  FOODS  COMMONLY 

USED  IN  MY  HOME? 

1.  Make  a  list  of  the  common  foods  used. 

2.  Test  some  of  these  for  starch,  sugar,  fat,  and  protein. 

3.  Consult  food  tables  in  books  to  learn  the  proportions  of  the 
different  nutrients  and  their  fuel  value  in  foods. 

Project  n.  —  To  OBTAIN  STARCH  FROM  POTATOES. 
i .   Look  up  a  method  or  device  by  which  you  can  separate  starch 
granules  from  potatoes. 

90 


COMPARISON  OF  THE  BODY  WITH  AN  ENGINE     91 

2.   Prepare  an  exhibit  to  show  what  you  have  done.    You  might 
show: 

(1)  Potatoes  equal  in  weight  to  those  used. 

(2)  The  starch  you  obtained. 

(3)  The  residue. 

(4)  A  chart  comparing  your  results  with  the  actual  amount 
of  starch  in  potatoes  as  learned  from  food  tables. 

(5)  A  written  report  of  your  work  and  results  including  an 
account  of  starch  factories,  possibly  illustrated  with  pictures. 

Project  III.  —  To  PLAN  FOR  ECONOMICAL  BUYING  FOR  OUR  FAMILY 

FOR  ONE  WEEK. 

1.  Determine  foods  and  amounts  of  each. 

2.  Determine  proportion  of  different  nutrients  needed. 

3.  Compare  costs. 

4.  Purchase  cheaper  foods  giving  required  nutrients. 

5.  Make  a  written  report  comparing  your  purchases  with  those 
of  the  previous  week.     Give  your  conclusions  before  the  class. 

Comparison  of  the  human  body  with  an  engine.  —  We 
have  already  compared  the  human  body  to  an  engine.  Let 
us  go  farther  with  this  comparison.  It  is  like  an  engine  in 
that  it  contains  very  many  complex  parts,  each  of  which 
has  some  particular  work  to  do ;  for  example,  the  fire  box, 
or  steam  chest  of  the  engine,  or  the  carburetor  of  a  gaso- 
line engine,  or  in  the  case  of  the  human  body,  there  are 
the  lungs  and  passages  leading  to  them,  the  food  tube 
with  its  different  complex  parts,  and  the  system  of  blood 
tubes  and  the  blood  within.  We  find,  moreover,  that  an 
engine  and  the  human  body  both  work  more  or  less  auto- 
matically, although  the  locomotive  is  controlled  from  the 
outside,  while  in  the  body  control  comes  from  within. 
Both  engine  and  body  need  fuel  in  order  to  do  work.  In 
order  to  release  the  energy  locked  up  in  the  fuel,  we  must 
have  oxygen  to  unite  with  it.  Both  engine  and  body  must 


92  THE  USES  OF  FOODS 

get  rid  of  the  waste  material,  for  no  engine  can  run  with 
its  fire  box  clogged  with  ashes,  nor  can  any  human  being 
live  long  without  getting  rid  of  wastes.  Neither  engine  nor 
body  can  be  overworked  without  breaking  down.  Rest 
has  been  found  to  be  necessary  for  metals  as  well  as  for 
man.  It  is  necessary  to  allow  the  most  smooth-running 


Fuel  gives  heat  and  energy,  and  makes  motion  possible.    (After  Hoadley.) 

machine  to  take  a  rest  now  and  then  if  the  machinery  is 
to  be  kept  in  good  condition. 

But  the  human  machine  differs  from  the  engine  in  some 
respects.  It  has  the  remarkable  ability  to  build  itself  out 
of  the  very  materials  that  are  put  into  it  as  fuel.  No 
engine  could  do  this.  Besides,  as  we  have  already  seen, 
germs  may  attack  the  human  body  and  render  it  unable  to 
carry  on  its  regular  work.  Owing  to  the  activity  of  these 
germs,  we  become  ill. 

What  the  body  is  made  of.  —  If  we  study  the  figure  on  the 
next  page,  we  find  that  the  human  body  is  made  up  of 
about  72  %  oxygen,  13.5  %  carbon,  9  %  hydrogen,  2.5  % 
nitrogen,  about  3  %  of  various  mineral  salts,  including  cal- 
cium, phosphorus,  potassium,  sulphur,  sodium,  chlorine, 
magnesium,  iron,  and  some  others.  All  of  these  substances 


WHAT  THE  BODY   IS  MADE  OF 


93 


mentioned  are  known  as  chemical  elements.  The  first  four 
named,  oxygen,  carbon,  hydrogen,  and  nitrogen,  are  the  ones 
which  are  of  most  interest  to  us  just  now,  as  they  form  the 
bulk  of  most  foods.  Carbon,  oxygen,  hydrogen,  and  nitrogen, 
for  example,  come  to  us  in  such 
foods  as  meats  and  vegetables. 
Water  supplies  much  of  the  hy- 
drogen and  oxygen.  One  ex- 
periment which  can  easily  be 
performed  at  home  will  show 
some  of  the  elements  contained 
in  foods. 

Experiment.  —  To  show  presence  of  car- 
bon and  water  in  foods. 

Materials:  Several  foods,  as  potatoes, 
meats,  oatmeal.  A  metal  plate  or 
small  piece  of  sheet  metal.  Burner. 
Glass  funnel.  Sugar.  Sulphuric 
acid.  A  500  cc.  beaker. 

Method  and  Results:  Place  a  small 
piece  of  the  food  to  be  tested  upon 
the  metal  and  heat  it.  Hold  the 
glass  funnel  over  it  as  a  test  for 
escaping  moisture.  Continue  heat- 
ing until  a  black  residue  is  left. 
What  in  all  probability  is  this  black 
substance  ? 

Strong  sulphuric  acid  has  such  attraction  for  water  that  it  will  withdraw 
the  water  from  many  plant  products  and  generate  enough  heat  to  sepa- 
rate it  from  the  black  carbon.  This  is  very  strikingly  done  with  sugar. 
Mix  60  grams  of  sugar  in  45  cc.  of  water  in  a  5oo-cc.  beaker  which  is 
set  on  a  plate.  Pour  60  cc.  concentrated  sulphuric  acid  into  the  sugar 
solution.  Result  ?  (If  performed  as  an  individual  pupil  experiment  use 
one  fourth  quantities  suggested.)  Can  you  name  the  black  product? 

Some  of  these  chemical  elements,  although  present  in 
very   small   quantities,   have   extremely   important   uses ; 


Chart  to  show  the  percentage  of 
chemical  elements  in  the  human 
body. 


94  THE  USES  OF  FOODS 

for  example,  it  has  recently  been  discovered  that  the 
beating  of  the  heart,  the  contraction  of  working  muscles, 
and  the  ability  of  our  nerves  to  send  messages  depend  upon 
the  presence  of  very  minute  quantities  of  calcium,  magne- 
sium, potassium,  and  phosphorus  in  the  body. 

Two  uses  of  foods.  —  Scientists  have  shown  us  that  our 
common  foods  are  made  up  of  substances  called  nutrients. 
These  nutrients  are  known  as  proteins,  fats,  carbohydrates, 
mineral  matter,  and  water.  Three  of  these  nutrients, 
protein,  fat,  and  carbohydrate,  are  consumed  in  the  body 
to  release  energy.  The  mineral  matter  serves  to  aid  in  the 
making  of  bone,  in  carrying  on  digestion,  and  in  other  body 
functions,  while  the  water  is  largely  used  as  a  vehicle  to 
carry  the  nutrients,  and  forms  a  very  large  percentage  of 
the  human  body.  Protein,  of  which  eggs,  lean  meat,  and 
the  germ  or  gluten  of  wheat  are  examples,  is  used  for  mak- 
ing body  material.  The  following  table  taken  from  a 
government  bulletin l  sums  up  the  uses  of  the  nutrients  to 
man. 

THE  FUNCTION   OF   THE   NUTRIENTS  IN   THE   BODY 


Protein Forms    tissue    (muscles, 

White  of  eggs  (albumen),         tendon,   and  probably 
curd   of  milk   (casein),         fat), 
lean    meat,    gluten    of 
wheat,  etc. 

Fats Form  fatty  tissue. 

Fat  of  meat,  butter,  olive 


All  serve  as  fuel  and 
yield  energy  in  form 
of  heat  and  muscular 
strength. 


oil,    oils    of    corn    and 
wheat,  etc. 

Carbohydrates Transformed  into  fat. 

Sugar,  starch,  etc. 
Mineral  matter  (ash)      .     .     Aid  in  forming  bone,  as- 
Phosphates  of  lime,  pot-         sist  in  digestion,  in  ab- 
ash, soda,  etc.  sorption  and  in  other 
ways    help    the    body 
parts  do  their  work. 

Water  is  used  as  a  vehicle  to  carry  nutrients,  and  enters  into  the  composition  of  liv- 
ing matter. 

1  Adapted  from  Atwater,  Principles  of  Nutrition  and  Nutritive  Value  of 
Food,  U.  S.  Department  of  Agriculture,  1902. 


HOW  TO  TEST  FOR  NUTRIENTS  IN  FOODS 


95 


Where  the  nutrients  are  found.  —  Carbohydrates  form 
the  chief  nutrient  in  the  foods  we  call  cereals,  breads, 
cake,  fleshy  fruits,  sugars,  jellies,  and  the  like.  Fats  and 
oils  are  found  in  nuts  and  some  grains,  and  make  up  the 
greater  part  of  bacon,  pork,  lard,  and  butter.  Animal 
foods  yield  our  chief  supply  of  protein.  White  of  egg  and 
lean  meat  are  almost  pure  protein  and  water.  Proteins 
are  most  abundant  in  those  plants  which  are  richly  sup- 
plied with  nitrogen  such  as  peas  and  beans,  grains  and  nuts. 


Foods  rich  in  protein.    (After  Tolman.) 

How  to  test  for  the  nutrients  contained  in  foods.  — 

Since  it  is  necessary  for  us  to  have  some  or  all  of  these 
various  nutrients  in  our  daily  diet,  it  will  be  interesting 
for  us  to  learn  how  to  determine  their  presence  in  foods. 
An  interesting  home  experiment  is  the  testing  of  as  many  of 
the  foods  which  make  up  your  daily  dietary  as  you  can. 

Experiment.  —  Tests  for  the  carbohydrates,  sugar  and  starch. 

Materials:   Starch.     Grape  sugar.     Iodine  solution.     Fehling's  solution. 

Test  tubes.     Various  foods  to  be  tested.     Bunsen  burner. 
Test  for  Starch:   Mix  a  little  starch  with  cold  water  and  heat  to  boiling 
in  a  test  tube.     Add  a  few  drops  of  iodine  solution.     The  resulting 
blue  or  blue-black  is  the  characteristic  test  for  starch.    The  test  may 


96  THE  USES  OF  FOODS 

be  made  on  cold  starch,  but  is  quicker  and  surer  if  the  substance  tested 
has  been  heated  to  the  boiling  point.  The  heat  causes  the  granules 
to  swell  and  burst  the  cell  walls  which  inclosed  them. 

Test  for  Grape  Sugar:  Place  a  little  grape  sugar  in  a  test  tube  one  fourth 
full  of  water.  Add  an  equal  amount  of  Fehling's  solution.  Heat  to 
the  boiling  point.  The  characteristic  brick  red  color  which  appears 
is  the  test  for  grape  sugar.  Cane  sugar  heated  or  digested  with  diluted 
acid  changes  in  part  to  grape  sugar,  but  pure  cane  sugar  will  give  no 
result  with  this  test. 

Test  many  foods,  as  oatmeal,  bread,  potatoes,  rice,  sirup,  molasses, 
cabbage,  apples,  bananas,  candy,  cheese,  meat,  etc.,  for  starch  and 
sugar.  List  the  foods  under  the  following  headings : 


MUCH  STARCH 

LITTLE  STARCH 

No  STARCH 

GRAPE  SUGAR 

Experiment.  —  To  test  for  fats  or  oils. 

Materials :   Pork  or  butter,  oily  nut,  corn  meal,  paper. 

Method  and  Results :  Rub  a  piece  of  pork  or  butter  on  a  piece  of  paper. 
Lay  a  crushed  nut  or  a  little  corn  meal  on  a  piece  of  paper  and  place 
it  in  a  warm  oven  for  a  few  minutes.  The  oil  or  fat  absorbed  by  the 
paper  makes  a  semi-transparent  spot  which  is  seen  when  held  toward 
the  light. 

Application:  Test  various  foods.  Those  which  give  a  test  without 
warming  in  the  oven  have  a  higher  per  cent  of  fat. 


Experiment.  —  To  test  for  protein. 

Materials:  White  of  egg  (a  typical  protein).  Test  tube.  Concentrated 
nitric  acid.  Ammonia. 

Method  and  Results:  Pour  the  white  of  egg  into  boiling  water  to  coagu- 
late it.  Pour  off  the  water  and  add  a  few  drops  of  strong  nitric  acid 
to  the  solid  white  of  egg.  Is  there  any  change?  Rinse  the  acid  off 
with  water  and  add  ammonia.  The  lemon  color  after  the  addition  of 
the  acid  and  the  deep  orange  following  the  addition  of  the  ammonia 
complete  the  test  for  protein.  Heat  quickens  the  reaction. 

Application  of  Test:  Try  this  test  on  such  foods  as  lean  meat,  bread, 
cheese,  beans,  and  rice.  Which  ones  show  the  presence  of  protein? 


THE  FOOD  REQUIREMENTS  OF  THE  BODY        97 


COMPOSITION  OF  FOOD  MATERIALS. 

••    EEED     cm    em    ^    »/-••.?• 


COMPOSITION  OF  FOOD  MATERIALS. 


WHITE  BREAD  WHOLE  WHEAT  BREA 

Water  35. i    W«ttr  J« 

Sa5LP'Otem-9Z     Prote.n  9  7 

09 


COMPOSITION  OF  FOOD**  MATERIALS. 


COMPOSITION  OF  FOOD  MATERIALS. 


SUGAR 


Foods  of  plant  origin.  Select  5  foods  containing  a  high  percentage  of  protein,  5  with  a 
high  percentage  of  carbohydrates,  5  with  a  high  percentage  of  water.  Do  vegetable 
foods  contain  much  fat  ?  Which  of  the  above-mentioned  foods  have  the  highest 
burning  value  ? 


H.-WHIT.   CIV.   SCI.   IN  THE  HOME  —  7 


98 


THE  USES  OF  FOODS 


COMPOSITION  OF  FOOD   MATERIALS. 

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COMPOSITION  OF  FOOtTMATERIALS. 

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COMPOSITION  OF  FOOD  MATERIALS. 

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COMPOSITION  OF  FOOD' MATERIALS' 

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h,d«t«»t  2  4 


Foods  largely  of  animal  origin.  Compare  with  the  previous  chart  with  reference  to 
amount  of  protein,  carbohydrate,  and  fat  in  foods.  Compare  the  burning  value  of 
plant  and  animal  foods.  Compare  the  relative  percentage  of  water  in  both  kinds 
of  foods. 


HOW  FOODS  ARE  PREPARED  FOR  USE  IN  BODY    99 

The  food  requirements  of  the  body.  —  For  some  time 
chemists  have  had  a  standard  of  measurement  for  heat 
given  off  when  substances  are  burned.  This  heat  unit 
is  called  a  calorie.  A  calorie  is  the  amount  of  heat 
required  to  raise  the  temperature  of  one  pound  of  water 
from  zero  to  four  degrees,  Fahrenheit.  The  burning  value 
of  foods  may  be  determined  and  measured  in  calories. 
Professor  Atwater  and  others,  by  means  of  a  series  of  in- 
teresting experiments,  endeavored  to  show  how  much 
fuel  is  needed  by  our  bodies  each  day,  as  well  as  the  amount 
of  building  material.  It  has  been  found,  for  instance, 
that  the  human  body  needs  from  three  to  a  little  over  five 
ounces  of  protein  each  day,  and  enough  fuel  food  to  furnish 
the  body  with  from  two  thousand  to  six  thousand  calories. 
We  may  adopt  as  our  standard  proportion  of  nutrients 
i  (protein):  i  (fat):  4  (carbohydrate).  Stated  in  another 
way  this  is  about  a  quarter  of  a  pound  of  protein,  a  quarter 
of  a  pound  of  fats,  and  a  pound  of  carbohydrates  each 
day  for  a  person  doing  moderate  work.  More  food  would 
be  needed  if  hard  work  had  to  be  done. 

How  foods  are  prepared  for  use  in  the  body.  —  We  all  use 
foods,  but  the  body  does  not  use  them  in  the  condition  in 
which  we  buy  them .  If  we  think  for  a  moment,  we  will  remem- 
ber that  food,  in  order  to  become  a  part  of  the  body,  has  to 
pass  through  the  wall  of  the  food  tube  and  get  into  the  blood, 
and  from  there  be  carried  to  the  place  where  it  is  to  be  used. 
You  cannot  pass  a  solid  material  through  a  thick  wall.  Ob- 
viously, the  food  tube  has  in  some  way  to  change  the  materi- 
als from  solids  into  liquids  so  that  they  can  get  through  this 
thick  wall.  This  process  of  changing  foods  into  a  liquid  con- 
dition which  enables  them  to  pass  through  the  walls  of  the 
food  tube  and  become  part  of  the  blood  is  called  digestion. 


IOO 


THE  USES  OF  FOODS 


Where  digestion  takes  place.  —  If  we  study  the  accom- 
panying diagram  of  the  digestive  tract  we  notice  that  there 
are  several  parts  to  it :  the  mouth,  with  the  tongue,  teeth, 
and  three  pairs  of  salivary  glands,  which  produce  saliva 

in  the  mouth.  Beyond 
the  mouth  a  smooth 
muscular  tube,  known 
as  the  gullet,  which 
leads  to  a  bag-like  or- 
.  gan,  called  the  stomach. 
Some  people  think  the 
stomach  is  the  organ  of 
digestion,  but  it  does 
only  a  part  of  the  work 
of  digestion.  The  stom- 
ach opens  into  the  small 
intestine,  which  in  the 
adult  is  a  much  coiled 
tube  about  thirty  feet 
in  length.  In  this  tube 
most  of  the  digestion 
takes  place.  Into  this 
part  of  the  tube  are 
poured  juices  from  two 
large  glands,  the  pan- 
creas and  the  liver. 
The  wall  of  the  small 
intestine  is  thrown  into  thousands  of  little  projections,  called 
wlli,  through  which  the  digested  food  is  absorbed  into  the 
blood.  The  large  intestine  is  the  last  part  of  the  food  tube. 
Near  the  junction  of  the  small  and  the  large  intestine  is  a 
little  sac,  the  vermiform  appendix,  about  which  most  of  you 


Ircxrg' 

Intestine 

3«vccll  . 
Intestine 


Apper\<a.i>c 


T^eotucrp^/ 


Digestive  tract. 


HOW  DIGESTION  TAKES  PLACE 


ici 


know.  This  is  an  organ  of  much  harm  and  little  use,  because 
of  the  disease  appendicitis  which  results  from  its  inflam- 
mation. 

How  digestion  takes  place.  —  It  is  not  so  easy  for  us  to 
understand  how  solid  foods  are  made  liquid  in  the  food 
tube,  but  perhaps  the  following  experiments  will  help. 
If  we  take  unsweetened  cracker  and  chew  it  for  some  time, 
we  notice  it  begins  to  taste  sweet.  A  cracker  is  composed 
largely  of  starch. 
Mix  some  powdered 
cracker,  or  starch, 
with  a  small  quantity 
of  water.  Pour  this 
mixture  into  a  fun- 
nel lined  with  filter 
paper,  and  allow  the 
substances  to  trickle 
through  into  a  test 
tube.  Take  grape 
sugar  of  equal  weight 
with  the  starch.  Mix 
with  as  much  water  as  before  and  filter  in  like  manner. 
We  can  prove  that  no  starch  comes  through  the  filter.  If 
we  test  the  water  that  drips  through  with  iodine,  it  does 
not  turn  dark  blue.  If  we  taste  the  water  which  has 
dropped  through  from  the  funnel  containing  the  sugar, 
we  find  it  is  sweet.  Evidently  sugar  passes  through 
this  wall,  while  starch  does  not.  An  experiment  per- 
formed with  unsweetened  crackers  shows  that  mixing  a 
cracker  thoroughly  with  saliva  causes  some  of  the  starch 
to  change  to  grape  sugar  (a  kind  of  digested  starch)  while 
cracker  moistened  with  water  will  not  be  changed.  This 


What  does  this  experiment  prove  ? 


1C? 


THE   USES  OF  FOODS 


change,  or  digestion,  is  caused  by  the  presence  in  the  saliva 
of  a  digestive  ferment  called  an  enzyme. 

Experiment.  —  To  show  digestion  of  starch  with  saliva. 

Add  a  few  drops  of  sodium  carbonate  solution  to  a  test  tube  a  third  full 
of  starch  paste.  Add  a  tablespoonful  of  filtered  saliva  warmed  to 
99  degrees  F.  Keep  it  at  this  temperature  on  the  water  bath.  At 
the  end  of  ten  minutes  test  a  portion  of  the  solution  with  Fehl- 
ing's  solution  to  see  if  any  of  the  starch  has  been  changed  to  sugar. 
Result? 

Enzymes  and  what  they  do.  —  We  shall  find  in  our  later 
study  that  enzymes  perform  an  important  work  in  the  body 
of  plants  and  animals.  They  are  the  active  parts  of  the 
digestive  fluids  and  cause  the  digestion  of  the  nutrients 

in  different  parts  of  the  food 
tube.  Starches  are  digested 
in  part  by  enzymes  supplied 
in  the  mouth,  and  in  part  by 
other  enzymes  in  the  small  in- 
testine. Proteins  are  digested 
by  enzymes  in  the  stomach 
and  intestines.  In  the  small 
intestine  fats  are  changed 
in  part  by  enzyme  action 
into  a  kind  of  soft  soap, 
in  which  form  they  enter  the 
blood. 

The  uses  of  the  teeth.  —  If 
you  study  the  accompanying 
diagram  of  the  teeth,  or  better,  your  own  mouth  before  a 
mirror,  you  will  notice  that  some  teeth  are  broad  and 
rather  irregular  on  the  upper  surface,  and  are  evidently 
used  for  grinding.  Others  are  sharp  or  pointed,  and  are 


I.  Teeth  of  the  upper  jaw,  from  below. 
7,  2,  incisors;  3,  canine;  4,  5,  pre- 
molars;  6,  7,  8,  molars.  II.  Section 
of  a  tooth.  £,  enamel;  D,  dentine; 
C,  cement ;  P,  pulp  cavity  into  which 
blood  vessels  and  nerves  pass  to  keep 
the  tooth  alive. 


MOVEMENT  OF  THE   FOOD   TUBE  103 

used  for  cutting  or  tearing.  The  long  tooth  of  a  dog  is  an 
excellent  example  of  a  tooth  fitted  for  tearing  purposes. 
Using  the  diagram,  divide  the  teeth  according  to  their 
uses,  and  name  them  from  the  chart,  as  — -  molars,  pre- 
molars,  canines,  and  incisors.  The  teeth,  with  the  assist- 
ance of  the  tongue,  prepare  the  food  for  digestion  by 
cutting  and  crushing  it,  so  that  when  the  tongue  pushes 
it  into  the  gullet,  it  will  be  in  better  condition  for  digestion. 
The  smaller  the  particles  of  food  the  more  surface  the  en- 
zymes have  to  act  upon,  and  consequently  the  more  rapidly 
digestion  takes  place  in  the  body.  There  is,  then,  a  real 
scientific  reason  for  chewing  the  food. 

Movement  of  the  food  tube  as  an  aid  to  digestion. — 
Perhaps  you  have  had  the  experience  of  losing  something 
held  in  the  mouth  by  having  it  slip  down  the  food  tube 
without  your  being  able  to  get  it  back  again.  As  this 
mysterious  movement  of  food  through  the  tube  takes  place 
just  as  well  when  we  are  lying  down  as  when  we  are  standing 
up,  it  is  evidently  not  due  to  the  force  of  gravity.  The  walls 
of  the  gullet,  the  stomach  and  small  intestines  are  muscular, 
and  are  constantly  in  motion.  The  stomach  itself  aids  more 
than  the  teeth  in 
making  the  particles 
of  food  smaller,  for 

the  food  after  it  is  i  ,.    . 

swallowed  is  turned 

Peristaltic  waves. 

over  and  over  again 

by  the  action  of  this  muscular  organ,  and  only  very  small 
particles  are  allowed  to  go  into  the  small  intestine.  The 
large  intestine  sends  along  the  food  by  means  of  wavelike 
movements.  This  movement,  called  peristalsis,  occurs  in 
both  small  and  large  intestines  and  is  of  great  importance 


104  THE   USES   OF   FOODS 

in  passing  foods  through  the  food  tube  and  in  expelling 
wastes  from  it. 

The  influence  of  the  mind  on  digestion.  —  Not  many 
years  ago,  it  was  discovered  in  experiments  with  the  X-ray 
machine  that  the  peristaltic  movements  of  the  food  tube 
were  stopped  or  arrested  when  a  cat  or  a  dog  was  frightened 
or  angry,  but  when  contented  and  happy  the  movements 
began  again  and  continued  normally.  These  experiments 
teach  us  a  very  real  lesson,  for  our  own  food  tube  acts  in 
the  same  manner.  Form  the  habit  of  contentment.  At 
meal  times  especially  learn  to  be  cheerful  and  happy. 
Laugh  and  grow  fat  is  a  statement  founded  on  simple 
scientific  fact. 

Some  reasons  for  differences  in  diets.  — It  goes  with- 
out saying  that  you  would  not  fill  up  the  fire  box  of 
your  furnace  with  as  much  coal  on  a  day  that  promised  to 
be  warm  as  on  a  cold  day.  Similarly  we  do  not  always 
need  the  same  amount  and  kind  of  food.  A  man  doing  hard 
work,  for  example,  would  need  very  much  more  energy- 
giving  food  than  a  man  doing  little  work. 

We  find  that  environment  plays  a  very  important  part  in 
diet.  People  living  in  hot  climates  need  different  foods  from 
those  in  cold  climates.  The  inhabitants  of  cold  countries 
need  more  heat-releasing  foods,  and  use  fats  for  this  pur- 
pose. In  summer  we  do  not  require  so  much  fat  as  we  do 
in  winter,  and  watery  foods,  such  as  fruits,  vegetables, 
milk,  eggs,  and  cereals,  are  better  than  much  meat  and 
fats.  Age  should  cause  a  difference  in  the  kind  of  food. 
We  take  food  in  order  to  make  new  body  material,  to  repair 
what  is  wasted,  and  to  give  us  energy.  Very  young  chil- 
dren grow  rapidly,  and  should  use  milk  largely  in  their  diet. 
A  study  of  the  diagram  will  show  you  the  reason  for  this. 


FOOD  ECONOMY 


105 


Milk  contains  all  the  food  nutrients,  and  in  about  the 
right  proportion  for  a  child.  Rapidly  growing  boys  and 
girls  require  more  food,  and  more  protein  food  than  do  those 
who  are  older.  As  a  rule  boys 
and  men  need  more  food  than 
girls  and  women. 

Each  one  of  us  must  deter- 
mine also  whether  he  or  she  can 
easily  digest  certain  kinds  of 
foods.  Some  of  us,  for  example, 
cannot  eat  strawberries  or  to- 
matoes without  suffering  from 
indigestion,  while  some  of  us  are 
able  to  eat  these  foods,  but  can- 
not take  others,  for  "  what  is  one 
another  man's 


globule$ 


IS 


Composition  of  milk.    What  per  cent 
is  water? 


man  s    meat 
poison." 

Food  economy.  —  A  study  of  the  table  on  page  106 
will  show  us  that  the  same  amount  of  money  will  buy 
vastly  different  amounts  of  energy  and  building  material 
in  food.  The  American  family,  as  a  rule,  does  not  expend 
its  money  wisely  in  foods.  We  should  eat  to  live,  and  not 
live  to  eat.  We  should  learn  to  like  and  use  cheaper 
foods  which  have  the  same  nutritive  value  as  do  the  more 
expensive  ones,  and  above  all  we  should  learn  to  eat 
more  fruits,  more  vegetables  and  cereals,  more  milk,  and 
less  meat,  because  meat  is  more  expensive,  and  because 
there  is  danger  of  eating  too  much  protein.  We  Americans 
are  fond  of  meats,  and  eat  more  than  is  good  for  us.  As 
a  result  we  make  some  of  our  organs  work  overtime  and 
put  a  strain  upon  them  in  order  to  get  rid  of  the  extra 
protein  which  forms  wastes  harmful  to  the  body. 


io6 


THE  USES  OF  FOODS 


PROTEIN                       FATS            CARBOHYDRATES        FUEL  VALUE 

FOOD 
MATERIALS 

£c 
fl 

H 

s  ., 

POUNDS  OF  NUTRIENTS  AND  CALORIES  OF  FUEL 
VALUE  IN  25  CENTS  WORTH 

10      — 

1  LB.                    2  LBS.                 3  LBS. 

CENTS 

POUNDS!                    2.OOO  CAL.        4.OOO  CAL.        6.OOO  CAL. 

Beef  .round 

35 

,,ta  POUNPS 

'")••  CALORIE 

Beef,  sirloin 

50 

Beef,  shoulder 

30 

[isr 

Mutton,  leg 

40 

fe 

(.0    R3=| 

Pork,  loin 
Pork,  salt,  fat 
Ham,  smoked 

30 
30 
45 

— 

.56  P 

Codfish,  fresh, 
dressed 

25 

Oysters,  90  cents 
per  quart 

45 

Milk,  15  cents 
Per  Quart 

Butter 

7K 
02 

3.33 

.40 

tmmm^m 

•1 

mmm^m^ 

Cheese 

40 

.63  Pj 

Eggs,  60  cents 
per  dozen 

40 

.63 

1 

•1 

Wheat  bread 

12^ 

2.00 

WMMMMb 

W 

Corn  Meal 

7 

S.fiO 

&$$$&ffifflfflffiffib 

%%$( 

Oat  Meal 

10 

2.50 

}  [ 

'7A 

Beans,  white,  dried 

12H 

2.00 

if 

ffifflffifflh 

Rice 

8 

3.00 

'MW/ 

Potatoes,  $1.50 

2M 

10.00 

W^M^^M^/, 

WflMfth 

Sugar 

10 

2.50 

^MftMttMsMfflfr, 

Wt^M^MZMb 

WMfa 

On  the  basis  of  cost  and  food  values  shown  in  the  above  table,  make  an  economical 
dietary  for  one  day  for  a  man  engaged  in  light  work.  Make  a  second  dietary  to  sat- 
isfy the  same  conditions  but  select  expensive  foods.  Give  reasons  for  the  amounts 
and  choice  of  foods  in  each  case.  What  is  the  difference  in  the  cost  of  these  two 
dietaries  ? 


VITAMINES  AND  THEIR  USES  107 

Vitamines  and  their  uses.  —  Recent  studies  have  shown 
that  some  foods  possess  peculiar  substances  known  as  wtam- 
ines  which  are  essential  to  health.  For  example,  one  of 


These  rats  are  the  same  age.  They  were  always  fed  the  same  kinds  and  amounts 
of  food,  namely,  bread  60%,  potatoes  20%,  greens  20%,  but  the  one  at  the  left 
had  in  addition  a  tablespoonful  of  milk  daily.  (Photo  from  Battle  Creek  Sani- 
tarium.) 


the  German  raiders  was  forced  to  put  in  at  Newport  News 
and  have  its  crew  interned  because  of  severe  illness  among 
them.  They  seemingly  had  all  the  food  necessary,  for  they 
had  sunk  ship  after  ship  and  had  taken  canned  goods, 
wheat  flour,  and  other  materials  in  abundance.  The  officers 
had  fresh  vegetables  from  time  to  time  while  the  crew  had 
none,  and  after  a  period  of  nearly  three  hundred  days,  a 
large  number  of  the  crew  became  so  ill  that  medical  at- 
tention was  necessary.  When  these  men  were  given  a  diet 
of  fresh  fruit,  milk,  eggs,  and  soups  made  of  boiled  skins  of 
vegetables,  they  were  cured  in  a  very  short  tune.  This 
seems  to  show  that  they  needed  the  vitamines  which  were 
present  in  skins  of  certain  vegetables.  The  chief  sources 
of  vitamines  for  us  are  the  outer  coats  of  rice  (unpolished  or 
brown  rice),  potatoes,  carrots,  and  some  other  vegetables; 
eggs,  milk,  and  many  fresh  fruits,  particularly  oranges  and 
pineapples. 


io8  THE  USES  OF  FOODS 

Marketing.  —  Most  mothers  and  fathers  do  the  market- 
ing for  the  family,  but  it  would  be  good  practice  for  girls 
and  boys  to  do  this  for  one  week.  They  would  find  it  would 
not  be  as  easy  as  it  seemed,  for  one  must  keep  in  mind  that 
the  cost  of  foods  has  little  relation  to  their  nutritive  value 
and  that  some  foods  that  cost  a  great  deal  have  a  low 
nutritive  value.  They  must  also  remember  that  the  family 
has  need  of  fuel  for  the  body  and  building  material  as  well 
which  must  be  supplied  by  foods.  If  you  will  study  the 
charts  on  the  preceding  pages,  you  will  find  that  all  of  these 
factors  must  be  taken  into  account  in  buying  for  the  family. 
An  excellent  home  project  would  be  for  each  boy  and  girl 
to  market  for  one  week,  and  to  bring  into  class  lists  with 
amounts  and  cost  of  each  article  purchased.  These  should 
be  placed  in  tabular  form,  giving  the  size  of  the  family, 
approximate  age  of  each  member  of  the  family,  and  all  other 
data  which  would  be  necessary  in  order  to  discuss  the 
material  brought  in.  Class  discussion  of  these  lists  would 
then  enable  you  to  decide  which  one  of  the  marketing 
lists  was  the  best.  Why  not  try  this? 

How  to  select  a  proper  menu.  —  A  practical  exer- 
cise which  will  enable  your  teacher  and  schoolmates  to 
determine  whether  you  have  understood  the  foregoing 
paragraphs  will  be  to  select  the  proper  foods  from  the 
three  following  lists,  for  breakfast,  lunch,  and  dinner 
respectively.  In  preparing  these  menus,  balance  the  diet, 
keeping  in  mind  your  own  occupation,  your  own  age,  your 
own  ability  to  digest  foods,  and  the  cost  of  foods. 

What  foods  could  you  substitute  for  meat  to  get  pro- 
teins? What  articles  on  the  rnenu  might  you  select  be- 
cause of  their  good  taste,  but  which  do  not  have  much  food 
value?  Should  such  articles  be  part  of  our  diet?  Which 


WHAT  COOKING  DOES  TO  FOODS 


109 


beverages  are  foods?  Which  are  not?  Can  you  give  good 
reasons  for  this  ?  In  connection  with  this  menu  study  the 
food  tables  and  all  diagrams  given  in  the  chapter. 


Cantaloupe 

Oranges 

Prunes 

Cornflakes 

Oatmeal 

Shredded  Wheat 


Beefsteak 
Boiled  Egg 
Fried  Lamb  Chop 
Fried  or  Hashed 

Brown  Potatoes 
Hominy 


BREAKFAST 

Griddle  Cakes  and     Apple  Sauce 


Maple  Sirup  Apple  Pie 

Whole  Wheat  Bread  Crullers 

Hot  Biscuits  Coffee 

Toast  Milk 

Butter  Tea 


LUNCH 

Chicken  Soup 

Shrimp  Salad 

Bread  and  Butter 

Peaches  and  Cream 

Corn  Soup 

Baked  Beans 

Hot  Biscuit 

Ice  Cream 

Vegetable  Soup 

Frankfurters 

Soda  Crackers 

Cocoa               Milk 

Fruit  Salad 

Dill  Pickles 

Doughnuts 

Soda  Water 

Potato  Salad 

Cheese 

Chocolate  Cake 

Tea 

DINNER 

Consomm6 

Boiled  Ham  with  • 

Stuffed  Peppers 

Peach  Pie 

Clam  Chowder 

Spinach 

Hearts  of  Lettuce 

Vanilla  Ice  Cream 

Pea  Soup 

Saddle  of  Lamb 

French  Dressing 

Chocolate  Ice  Cream 

Olives 

Planked  Steak 

Lobster  Salad 

Grapes 

Celery 

Mashed  Potatoes 

Fruit  Salad 

Nuts 

Pickles 

Baked  Potatoes 

Waldorf  Salad 

Raisins 

Fried  Filet  of  Sole 

Potatoes  Lyonnaise 

Italian  Salad 

Edam  Cheese 

Boiled  Whitefish 

Peas 

Bread 

Roquefort  Cheese 

Saratoga  Chips 

String  Beans 

Rolls 

Tea 

Roast  Lamb  with 

Cauliflower 

Butter 

Cocoa 

Brown  Gravy 

Beets 

Strawberry  Pie 

Milk 

Fried  Chicken 

Rice 

Apple  Pie 

Coffee 

What  cooking  does  to  foods.  —  If  we  were  to  examine  a 
bit  of  raw  potato  under  the  microscope,  we  would  find 
that  the  starch  contained  in  it  was  placed  in  little  pockets 
surrounded  by  thick  walls.  Examination  of  a  bit  of  cooked 
potato  under  the  microscope  will  show  quite  a  different 
condition.  The  walls  around  the  starch  cells  are  broken 
and  the  starch  swelled  and  softened.  Cooking  breaks  down 


no 


THE   USES  OF   FOODS 


FOODS  ADAPTED  TO  DIFFERENT  AGES,  CLASSIFIED  ACCORDING  TO  WHAT 
THEY  Do  FOR  THE  BODY 

Numbers  are  placed  after  some  foods  to  show  that  they  do  important  work  under  the  column 
headings  of  those  numbers. 


FOOD  PRIMARILY  FOR  GROWTH 

FOOD  PRIMARILY  FOR  HEAT  AND  WORK 

AND  REPAIR 

(ENERGY) 

I 

II 

III 

IV 

V 

Rich  in  Protein 

Rich  in  Mineral 
Matter 

Rich  in  Fats 

Carbohydrates 
Starches 

Carbohydrates 
Sugars 

Builds  and   repairs 

Builds    bone 

Stimulate 

Yield     energy; 

Yield  energy  for 

muscle 

Body  activities 

growth 

heat  and  work 

heat  and  work 

FOODS  SUITABLE  FOR  INFANTS 

Milk  —  II,  III,  V 

Milk  —  I,  III,  V 

Cream  —  I.  II 

Gruels  —  I,  II 

Orange  juice  •  — 

human,  modified 

Egg    yolk  —  I 

used  to  enrich 

made    f  r  om 

II 

cow's 

Orange    juice, 

cow's  milk 

oats,   barley, 

Prune    juice  — 

Beef  juice  —  II 

Prune  juice 

whole  wheat 

II 

FOODS  TO  BE  ADDED  AFTER  THE  FIRST  YEAR 

Milk  —  II,  III,  V 

Soups   —    III, 

Egg  —  I,  II 

Breakfast  foods 

Prunes    --    II 

Eggs—  11,111 

Fruits  —  V 

Cream  —  I,  V 

I,  II 

stewed  ;       in 

Poultry  —  II,  III 

Greens  —  III 

Whole  milk  - 

Potatoes  —   I 

puddings 

Meats  —  II,  III 

Meat    broths 

I,  II,  V 

Rice  —  I 

Apples    —    II 

(in  limited 
amounts) 

with      vege- 
tables —  III 

Butter  —  II 

Sweet  potatoes 

—  nVv 

stewed  ; 
baked 

FOODS  SUITABLE  FOR  ANY  ONE  OVER  FIVE  YEARS 

Fish  —  II,  III 

Vegetables 

Following    fats     Chestnuts 

All     fruits     in 

(green- 

may  be  defi-  {      II 

jam    or   pre- 

Cheese —  II,  III 

leaved) 

cient    in    fat     Squash  —  II 

serves,      and 

Cabbage  —  raw 

solublesi  Pumpkins  —  V 

candied    or 

Beef  —  II,  III 

as  a  salad,  as 

which    stim- 

Bananas —  II, 

glace^ 

Veal  —  II 

vegetable 
Cauliflower 

ulate  growth. 
Use  them   in 

V 
Rice  —  II 

Apples  —  II 
Peaches  —   II 

Artichokes 

cooking 

a.  Polished 

Apricots  —  II 

Mutton  —  II,  III 

Tomatoes 

Oleomargarine 

b.  Rice   flour 

Raisins  —  II 

Pork  —  II,  III 

Egg  plant 
Green    peppers 

—  II 
Peanuts   —    I, 

Wheat       prod- 
ucts —  I,  II 

Dates  and  figs 

(sweet) 

II,  IV 

a.  Flour 

All  jellies 

Soybeans  —  II,  III, 

Cucumbers 
Onions 

Suet 
Goose  fat 

b.  Macaroni 
c.  Cream    of 

Honey  — 
replaces  sug- 

Beets and  tur- 

Chicken fat 

wheat 

ar     in     pre- 

Peanuts —  II,  III, 

nips  —  V 

Mutton  fat 

d.  Shredded 

serves,     can- 

IV 

Radishes 

Clarified  and 

wheat 

dies,         and 

Parsnips 

mixed     with 

Corn    products 

cakes 

Beans     (dried)     — 

Watermelon  — 

suet  or  cot- 

— I,  II 

Molasses  — 

II,  IV 

raw,    pickled 

tonseed      oil 

a.  Corn  meal 

replaces  sug- 

Cantaloupe 

it  makes  an 

b.  Corn  flour 

ar  in  candies 

Lentils  —  II,  IV 

Pickles    of    all 

excellent 

c.  Hominy 

and  cakes 

Peas  (dried)  —  II, 

kinds 
Fruits   —   raw 

butter     sub- 
stitute      for 

Barley  products 

Maple  sugar 
Grape  juice  — 

IV 

or  cooked 

cookery 

Rye     products 

II 

Food     value 

Salt  pork 

—  I,  II 

All  candies 

Nuts  —  II,  III,  IV 

depends  upon 
amount  of 

Lard 
Bacon  —  I 

Oat      products 

All  sirups 
Cane    or    beet 

Cereals  —  II,  III, 

sugar  added 

Olive  oil 

Buckwheat 

sugar 

IV 

Dried    fruits 

Cottonseed    oil 

products    - 

Sweet  cakes  — 

and     v  e  g  e  - 

Peanut  oil 

I,  II 

I,  II,  III, 

Gelatine 

tables 

Corn  oil 

Tapioca 

Sweet    desserts 

From  chart  prepared  by  the  Department  of  Home  Economics  University  of  Michigan. 


DIFFERENT  METHODS  OF  COOKING  lit 

and  softens  the  tough  walls  of  the  cells  in  vegetables,  and 
in  the  case  of  meats  makes  them  less  tough  and  renders 
them  more  palatable,  and  thus  helps  in  their  digestion. 
More  than  this,  especially  in  meats,  cooking  destroys 
organisms  which  might  grow  if  taken  into  the  body. 
Thus  cooking  makes  foods  safe  which  otherwise  might  be 
harmful. 

Different  methods  of  cooking.  — -  In  general  there  are 
four  principal  ways  of  cooking  foods,  boiling,  broiling,  fry- 
ing, and  baking.  In  boiling  we  place  the  food  in  water  and 
heat  to  212  degrees  Fahrenheit.  White  of  egg  coagulates 
or  hardens  above  140°  F.  An  excellent  method  of  cooking 
eggs  is  therefore  either  to  poach  them  in  water  just  below 
boiling  or  to  place  the  eggs  in  a  dish  of  boiling  water,  cover, 
take  off  the  stove  and  leave  for  seven  minutes.  They 
will  be  found  to  be  cooked  and  the  white  will  be  quite 
digestible.  Milk  should  not  be  boiled,  for  this  injures 
the  protein.  In  making  soups,  where  we  wish  to  draw 
the  nutriment  into  the  water,  the  material  should  be  put 
into  cold  water,  brought  to  the  boiling  point,  and  then 
boiled  slowly.  If  we  wish  to  keep  the  nutriment  in  the 
material,  it  should  be  put  at  once  into  boiling  water. 
In  roasting  and  broiling  use  a  high  temperature  at  first. 
A  hot  fire  should  be  used  in  cooking  a  steak  so  as  to 
keep  the  nutriment  within  the  browned  surface.  A 
seared  covering  prevents  the  escape  of  juices.  Frying 
is  not  a  desirable  method  of  cooking  because  fat  is  likely 
to  soak  into  the  foods,  thus  rendering  them  less  digest- 
ible. In  baking,  the  food  should  be  placed  in  a  hot  oven 
first  and  then  the  heat  reduced  so  that  the  inside  of 
the  substances  can  be  cooked.  Cooking  starch  at  baking 
temperature  changes  it  to  dextrin,  which  is  more  easily 


112 


THE  USES  OF  FOODS 


digested  than  starch.     The  browning  of  the  bread  crust  is 
due  to  this  change. 

Fireless  cooker.  —  In  these  days  nearly  every  household 
is  provided  with  a  labor-saving  device  known  as  the  tireless 
cooker.  An  interesting  home  project  would  be  the  manu- 
facture of  such  a  cooker.  The  principle  of  the  tireless  cooker 

is  that  of  insulation. 

''  The     food     to     be 

cooked  is  placed  hot 
in  the  metal  con- 
tainer inclosed  in  a 
box  with  heat  insu- 
lating material  filling 
the  space  between  it 
and  the  outer  part 
of  the  box,  while  a 
hot  soapstone  or 
cast  iron  radiator 
is  placed  under  the  container.  In  this  way  after  the 
covers  are  tightly  fastened,  the  food  cooks  slowly,  and  its 
flavor  is  preserved.  In  addition  to  this  time  and  fuel  are 
saved. 

Scoring  my  foods  and  dietary.  —  Probably  no  score  card 
is  more  difficult  for  you  to  use  than  this  one  and  yet  none 
is  more  important.  If  you  can  make  this  a  summary  of 
what  you  have  learned  about  the  uses  of  foods  and  then 
apply  this  knowledge  in  your  daily  life  your  time  will  have 
been  well  spent.  In  this  card  you  will  doubtless  find  im- 
portant matters  that  have  not  been  touched.  If  you  want 
to  add  or  subtract  or  change  any  part  of  the  card  do  so  and 
have  the  class  discuss  the  change  with  you,  for  in  this  way 
you  may  do  some  real  constructive  work  in  science. 


Fireless  cooker. 


SCORING  MY  FOODS  AND  DIETARY 


SCORE   CARD.     FOODS   IN   MY   HOME 


MY  SCORE 

EXCELLENT 

FAIR 

VERY  POOR 

TOTAL 

A    BAL- 

Menu varies   under 

Variation    10%    to 

If  any  one  group  is 

ANCED 

10%  from   i    (pro- 

50% (5) 

omitted  (o) 

DIET 

tein):     i    (fat):    4 

(carbohydrate)  (10) 



RIGHT  DIET  FOR  OCCUPATION,   SEASON,  AND  ENVIRONMENT. 

More  food  for  heavy  work  (2)     Less  protein  in  hot  weather  (2)     More 

watery  foods  in  hot  weather  (i)     More  fats  in  cold  weather  (i)     Milk  at 

all  times  (4) 

FOODS 

Meats    broiled, 

Fried       meats    not 

Fried   meats    three 

PROPERLY 

roasted,  never 

more    than    once 

times  a  week  or 

COOKED 

fried  (2) 

a  week  (i) 

more  (o) 

.... 

Cereals  well  cooked 

Uncooked  prepared 

No  cereals  (o) 

(2) 

cereals  (i) 

Vegetables      boiled 

Vegetables     boiled 

Vegetables     under- 

slowly    in    little 

rapidly  but  done 

cooked  and  rap- 

water (2) 
Puddings,  no  fried 

d) 
Fried    desserts    in- 

idly boiled  (o) 
Fried   desserts   fre- 

desserts or  pies  (2) 
Raw     foods     thor- 

frequently (i) 
Raw  foods  usually 

quently  (o) 
Raw    foods    never 



oughly  washed  (2) 

washed  (i) 

washed  (o) 

COST   OF 

Expensive    cuts    of 

Expensive   cuts    of 

Expensive   cuts    of 

FOODS 

meat  omitted  (2) 

meat  once  a  week 

meat   every   day 

CONSID- 

(i) 

(o) 

ERED 

Vegetables    out    of 

Vegetables    out    of 

Vegetables    out    of 

season      omitted 

season     twice     a 

season  regardless 

(2) 

week  (i) 

(o) 

Cereals  and  canned 

Canned   goods  but 

No   substitutes   for 

vegetables     used 

never  cereals  sub- 

fresh   vegetables 

when  fresh    ones 

stituted  for  fresh 

(o) 

are  high  (2) 

vegetables  (i) 

Cheap   fruits   used 

Expensive        fruits 

Expensive        fruits 

(2) 

infrequently  (i) 

often  used  (o) 

Home        produced 

Home  grown  foods 

Home  grown  foods 

foods  used  (2) 

infrequent  (i) 

never  used    (o) 

EASILY 

Foods      selected 

Foods      sometimes 

Foods     never     se- 

DIGESTED 

every  day  for  vi- 

selected    for    vi- 

lected  for  vitam- 

FOODS 

tamines  (i) 

tamines  (A) 

ines  (o) 

SELECTED 

Fruit      on      menu 

Fruit      on      menu 

Fruit    infrequently 

twice  a  day   (2) 

once  a  day  (i) 

on  menu  (o) 

Milk  on  menu  three 

Milk  on  menu  once 

Tea    or    coffee    in- 

times a   day  for 

a    day    for    chil- 

stead of  milk  (o) 

children  under  15 

dren;     no  tea  or 

(2) 

coffee  (i) 

Cereals  and   bread 

Cereals     or     bread 

Cereal  rarely  used 

used     frequently 

once  a  day  only 

(o) 

(i) 

(i) 

Rice     or    potatoes 

Rice     or    potatoes 

Rice     or     potatoes 

used     frequently 

infrequently  (A) 

used  rarely  (o) 

(i) 

No  rich  desserts  (i) 

Infrequent  (5) 

Frequent   (o) 

Have     learned     to 

Have  learned  a  few 

Have  learned  them 

omit  foods  I   do 

foods  I  cannot  di- 

but  continue    to 

not  digest  (i) 

gest  (|) 

eat  them  (o) 

Laxative  foods  once 

Laxative  foods  in- 

Laxative foods  not 

a  day  (i) 

frequently  (5) 

considered  (o) 

GRAND   TOTAL 

H.-WHIT.   CIV.   SCI.   IN  THE  HOME  —  8 


H4  THE  USES  OF  FOODS 

REFERENCE   BOOKS 

Broadhurst,  Home  and  Community  Hygiene,  Chapter  III  (Teacher's  use).  J.  B. 
Lippincott  Company. 

Bulletin  13,  American  School  of  Home  Economics,  Chicago. 

Human  Nutrition,  Bulletins  6  and  7.     Cornell  Reading  Course. 

Davison,  The  Human  Body  and  Health.     American  Book  Company. 

Fisher  and  Fisk,  How  to  Live,  Chapter  II.     Funk  and  Wagnalls. 

Hunter,  A  Civic  Biology,  Chapters  XIX,  XX.     American  Book  Company. 

Hunter,  Laboratory  Problems  in  Civic  Biology  (For  teachers).  American  Book 
Company. 

Lusk,  Food  in  War  Time.     W.  B.  Saunders  Company. 

Ritchie,  Physiology  and  Sanitation,  Chapters  VII,  VIII,  IX.  World  Book  Com- 
pany. 

Rose,  Feeding  the  Family.     The  Macmillan  Company. 

Stiles,  Nutritional  Physiology  (For  teachers).     W.  B.  Saunders  Company. 

Stiles,  Human  Physiology,  Chapters  XXV,  XXVI.    W.  B.  Saunders  Company. 


CHAPTER  VII 

PURE   FOOD   IN   THE   HOME 

Problems.  —  i.    To  learn  what  causes  food  to  spoil. 

2.  To  find  out  how  yeast  assists  in  bread  making. 

3.  To  discover  methods  of  keeping  foods  for  long  periods 
of  time. 

4.  Why  is  there  a  difference  in  the  efficiency  of  different 
refrigerators  ? 

5.  To  discover  the  most  favorable  conditions  for  the  growth 
of  bacteria. 

Experiments.  —  i.   How  and  why  yeast  is  used  in  bread  making. 

2.  What  conditions  are  favorable  and  what  unfavorable  for  the  growth 
of  bacteria? 

3.  What  effects  have  different  preservatives  upon  bacteria? 

Project  I.  —  TESTING  AND  PRESERVING  EGGS  FOR  HOME  USE. 

1.  TESTING.    Devise  means  for  testing  quality  of  eggs.    (Candling; 
10%  brine  solution.)     Make  test  of  fresh,  stale,  and  good  storage 
eggs.     (See  United  States  Department  Agriculture,  Farmers'  Bulle- 
tin No.  471,  and  Sherman's  Food  Products,  page  144.) 

2.  PRESERVING.     Methods    in  use?     Principle  of    preservation? 
Why  must  fresh,  clean,  and  unwashed  eggs  be  used  when  preserving 
in  water  glass? 

3.  COST  OF  EGG  SUPPLY.     Prices  paid  for  eggs  at  different  sea- 
sons?   'How  many  eggs  in  a  year?    What  saving  would  be  made  by 
preserving  three  fourths  of  this  supply? 

"S 


n6  PURE   FOOD   IN   THE   HOME 

Project  II.  —  To  PASTEURIZE  YOUR  HOME  MILK  SUPPLY. 

If  your  milk  is  purchased  is  there  any  evidence  to  indicate  whether 
or  not  it  has  been  pasteurized?  What  is  the  evidence?  Reasons  why 
you  prefer  pasteurized  milk?  Devise  apparatus  for  pasteurization. 
What  temperature  will  you  use?  Give  in  your  report  a  full  account 
of  new  facts  learned,  diagram  of  apparatus,  and  results  secured. 

Thought  Question. 

In  a  test,  50  pounds  of  ice  were  put  into  the  refrigerator  on  a  warm, 
muggy  day.  The  refrigerator  was  opened  when  necessary  to  put 
in  and  to  take  out  food.  All  the  drip  water  going  from  the  refrig- 
erator  was  saved  and  weighed.  It  weighed  more  than  50  pounds. 
Explain  why. 

Why  foods  spoil.  —  We  are  well  aware  that  foods  do  not 
keep  indefinitely.  Peaches,  pears,  and  apples  rot;  eggs, 
meat,  and  fish  spoil;  and  milk  and  cooked  cereals  become 
sour.  Why  does  this  happen?  We  know  that  if  foods 
are  placed  in  the  ice  box  they  will  not  spoil  so  soon.  We 
know  that  if  we  boil  certain  kinds  of  foods  they  are  less 
likely  to  spoil,  and  we  are  all  familiar  with  the  use  of  canning 
as  a  means  of  keeping  foods ;  but  why  do  foods  become 
unfit  for  use  eventually  ?  Take  small  quantities  of  several 
different  kinds  of  foods,  for  example,  milk,  a  piece  of 
meat,  potatoes,  and  cooked  cereal,  divide  each  food  into 
two  equal  portions,  and  place  in  separate  dishes  or  jars; 
seal  tight.  Place  these  jars  in  a  large  dish  of  water 
and  boil  them  for  one  hour.  After  this  boiling  we  are  sure 
that  everything  that  might  have  been  living  in  the  jars  is 
dead.  If  we  now  open  one  jar  of  each  food,  keeping  the  other 
closed,  and  examine  their  contents  after  four  or  five  days, 
we  shall  find  that  in  the  open  jars,  the  food  has  begun  to 
spoil,  while  in  the  closed  jars,  it  is  still  good.  Comparing 
this  with  our  previous  experiments  with  the  air,  we  may 
conclude  that  whatever  causes  the  food  to  spoil  must  come 


YEASTS  AND  WHAT  THEY  DO 


117 


from  the  air  which  is  in  contact  with  the  food.  As  a  matter 
of  fact  this  is  true.  The  tiny  plants  of  the  home  —  yeasts, 
molds,  and  bacteria  —  are  always  present  in  the  air,  al- 
though we  cannot  see  them,  and  when  they  lodge  on  food 
and  grow,  they  cause  certain  changes  to  take  place  in  the 
food.  These  changes  cause  the  food  to  have  an  unpleasant 
taste  and  odor.  In  fact,  its  quality  is  so  changed  that  it  is 
no  longer  suitable  to  eat. 

Yeasts  and  what  they  do.  —  All  boys  and  girls  who  live 
in  the  country  know  that  apple  juice  or  grape  juice,  if 
allowed  to  stand  exposed  to  the 
air,  will  very  soon  ferment,  that 
is,  little  bubbles  will  appear  in 
the  liquid,  and  a  prickly,  pun- 
gent taste  is  noticeable.  The 
yeast  changes  the  sugars  in  the 
fluid  to  alcohol  and  carbon  di- 
oxide is  formed.  The  escaping 
bubbles  of  this  gas  may  be  seen 
as  the  liquid  ferments.  Yeasts 
are  tiny  plants  made  up  of  a 
single  cell  or  unit  of  building  material.  They  grow  very 
rapidly  under  favorable  cond'tions.  These  conditions  can 
be  easily  shown  by  a  home  experiment.1  Yeasts  are  useful 
in  commercial  industries  which  make  use  of  fermentation. 
They  are  of  great  value  also  in  the  home  in  causing  bread 
to  rise. 

Experiment.  —  How  and  why  yeast  is  used  in  bread  making. 

Materials:    Flour.    Water.     Sugar.     Salt.    Lard.    Yeast  cake.     Bak- 
ing tins. 
Method:  Make  a  dough  by  mixing  the  flour,  sugar,  salt,  lard,  and  water 

1  See  Hunter's  Civic  Biology,  page  137. 


Yeast  plant. 


Ii8  PURE  FOOD  IN  THE  HOME 

to  form  a  thick  paste.  Add  a  little  yeast  which  has  been  mixed  with 
lukewarm  water.  Divide  this  into  three  parts.  Keep  the  first  of 
these  at  a  temperature  of  85  to  90  degrees,  the  second  in  a  cold  tem- 
perature, and  the  third  at  the  room  temperature,  say  about  70  degrees, 
for  several  hours.  Then  bake  the  three  samples. 

Observation:   Compare  the  three  lots  for  appearance,  texture,  and  taste. 

Conclusion:  How  do  you  account  for  the  pores  in  the  bread?  What 
caused  the  bread  to  rise?  Under  what  conditions  does  the  rising  take 
place  best? 

Bread  making.  —  Most  of  us  are  familiar  with  the  pro- 
cess of  bread  making.  The  materials  used  are  flour,  milk 
or  water  or  both,  salt,  some  butter  or  lard,  a  little  sugar 
and  yeast.  The  sugar  hastens  the  process  of  fermenta- 
tion, or  "  rising,"  as  it  is  called.  After  mixing  the  mate- 
rials thoroughly,  the  dough  is  put  in  a  warm  place  (about 
75°  Fahrenheit)  to  "rise."  If  we  examine  the  dough  after 
some  hours,  we  find  it  filled  with  holes,  which  give  the  mass 
a  spongy  appearance.  The  yeast  plants,  owing  to  favorable 
conditions,  have  grown  rapidly  and  made  the  cavities  with 
carbon  dioxide.  Alcohol  is  present,  too,  but  this  is  evapo- 
rated when  the  dough  is  baked.  The  baking  cooks  the 
starch  of  the  bread,  drives  off  both  the  carbon  dioxide  and 
alcohol,  and  kills  the  yeast  plants,  besides  forming  a  crust 
on  the  loaf. 

Molds  in  the  home.  —  One  of  the  most  common  enemies 
of  food  in  the  home  is  mold.  If  you  place  two  pieces  of 
bread,  one  kept  moist,  and  the  other  dry,  side  by  side  in 
the  kitchen  or  living  room,  the  dry  bread  will  remain  un- 
changed and  a  fuzzy  growth  will  soon  appear  on  the  moist 
bread.  This  fuzzy  growth  later  turns  black.  This  growth 
is  composed  of  a  large  number  of  little  mold  plants  (see 
figure)  which  take  root  on  the  surface  of  the  bread,  obtain 
their  food  from  it,  grow  in  time  so  as  to  cover  it,  and  produce 


CONDITIONS  FOR  THE  GROWTH  OF  BACTERIA      119 


little  upright  fruiting  bodies.  These  fruiting  bodies  bear 
tiny  little  seedlike  structures,  called  spores,  which  are 
blown  around  in  the  air,  and  grow  under  favorable  condi- 
tions. What  are  these  conditions?  Refer  to  your  two 
pieces  of  bread.  Warmth  and  moisture  are  necessary  for 
the  growth  of  all  tiny  organisms.  Molds  do  considerable 
damage,  although 
they  do  not  render 
foods  completely  un- 
fit to  eat.  You  all 
remember  scraping 
the  layer  of  mold 
from  cheese,  before 
using  it.  As  a  mat- 
ter of  fact,  certain 
cheeses  get  their 
flavor  from  the 
molds  that  grow  in 
them.  Molds  also 
attack  other  organic 
materials  besides 
foods.  They  grow 
on  shoes,  leather,  paper,  or  even  moist  wood.  At  least  one 
troublesome  skin  disease,  called  ring  worm,  is  due  to  the 
growth  of  molds  in  the  skin. 

Conditions  favorable  for  the  growth  of  bacteria.  —  By  far 
the  most  important  enemies  of  pure  foods  are  bacteria,  which 
cause  food  to  decay.  We  can  show  the  factors  which  in- 
fluence the  growth  of  bacteria  by  the  following  experiment : 

Experiment.  —  What  conditions  are  favorable  and  what  unfavorable  to  the 

growth  of  bacteria  ? 
Materials:  Beans.    Test  tubes. 


Three  different  types  of  mold  plant.  Notice  the  fruit- 
ing bodies,  containing  spores,  i.  Cheese  mold. 
2.  Corn  smut.  3.  Bread  mold. 


120  PURE   FOOD   IN  THE   HOME 

Method:  Soak  half  of  the  beans  in  water  overnight.  Crush  them  and 
place  a  portion  in  each  of  three  different  test  tubes.  Add  a  few  drops 
of  water  to  each  test  tube.  Place  one  of  these  test  tubes  where  it  will 
be  kept  warm,  about  90  degrees.  Place  another  in  the  refrigerator, 
close  the  third  with  a  wad  of  cotton  and  heat  to  the  boiling  point. 
Crush  one  or  two  of  the  dried  beans  and  put  them  in  a  test  tube  in  a 
warm  place.  Compare  the  odor  in  these  tubes  in  three  days. 

Conclusion:  In  which  ones  is  decay  taking  place?  Is  this  due  to  action 
of  bacteria  ?  Why  do  you  think  so  ?  Name  at  least  two  conditions 
which  favor  bacterial  growth  and  two  conditions  which  are  unfavorable 
to  it. 

The  experiments  show  us  that  bacteria  need  moist 
food  and  a  warm  temperature  in  order  to  grow  well.  Grains, 
crackers,  dried  fish,  and  dried  fruits  all  are  examples  of 
foods  which  keep  well  because  they  contain  very  little  water. 
Boiling  or  sterilizing  kills  bacteria.  It  can  be  shown  that 
they  need  air,  and  that  light  is  unfavorable  for  their  rapid 
growth.  Sunlight  is  known  to  be  one  of  the  best  germ 
killers  we  have.  For  that  reason  sunlight  is  important  in 
both  sleeping  and  living  rooms. 

Foods  most  easily  spoiled  by  bacteria.  —  If  you  were 
to  select  a  large  number  of  different  foods  and  test  them 
to  determine  in  which  bacteria  grow  most  rapidly,  you 
would  find  that  the  foods  containing  moisture;  and  a  large 
amount  of  protein,  are  most  favorable  for  bacterial  growth. 
As  the  bacteria  feed  on  this  protein,  it  falls  to  pieces  and 
eventually  rots.  It  is  broken  down  by  the  action  of  bac- 
teria into  gases,  liquids,  and  some  solids.  It  has  a  char- 
acteristic "  rotten "  odor,  and  poisons  which  come  as  a 
result  of  the  work  of  the  bacteria.  Some  of  the  poisons 
are  called  ptomaines.  No  food  should  be  eaten  that 
smells  badly  or  appears  to  be  decayed.  The  use  of  com- 
mon household  preservatives  in  checking  bacterial  action 
may  be  seen  from  this  experiment. 


HOW   TO   KEEP   GERMS   FROM    SPOILING   FOODS      121 


Experiment.  —  What  effect  have  different  preservatives  upon  bacteria  ? 

Materials:    Beans.     Test  tubes.     Salt.     Sugar.     Vinegar.     Boric  acid. 

Method:  Soak  beans  in  water  overnight  and  crush  them.  Put  a  portion 
into  each  of  seven  test  tubes.  Add  water  to  cover.  Set  one  tube 
aside;  add  preservatives  as  follows:  No.  i,  untreated;  No.  2,  one 
fourth  teaspoonful  of  salt;  No.  3,  one  fourth  teaspoonful  of  sugar; 
No.  4,  one  teaspoonful  of  sugar;  No.  5,  one  fourth  teaspoonful  of 
vinegar;  No.  6,  one  teaspoonful  of  vinegar;  No.  7,  a  pinch  of  boric 
acid.  Leave  these  tubes  open  in  a  warm  room.  A  bad  odor  will 
result  from  bacterial  growth.  Test  for  odors  every  two  days  for 
two  weeks.  Make  tabulated  form  for  recording  the  result  of  the  test. 

Preservatives  and  their  use.  —  Foods  are  often  protected 
against  bacteria  by  adding  substances  in  which  bacteria 
cannot  live  and  develop.  Such  materials  as  salt,  sugar, 
vinegar,  and  some 
spices  are  harmless 
preservatives.  In  re- 
cent years,  other  sub- 
stances, such  as  ben- 
zoate  of  soda,  borax, 
or  boracic  acid  have 
come  to  be  used 
as  preservatives,  but 
the  latter  materials 
are  harmful,  espe- 
cially when  used  in 
large  quantities. 

How  may  we  keep 
germs  from  spoiling 
foods  ?  —  From  the 


Cold  storage  meat  warehouse. 


experiments  that  we 

have  performed,  we 

find  that  intense  heat  and  intense  cold  prevent  the  growth 

of  germs.     Bacteria  are  prevented  from  growing  in  foods 


122 


PURE   FOOD  IN  THE  HOME 


SECTION  -THROUGH  WALI/ 


while  kept  in  cold  storage  from  six  months  to  two  years  or 
more.  But  we  must  remember  that  intense  cold,  while  it 
prevents  the  growth  of  bacteria,  does  not  kill  them,  and 

cold  storage  foods,  if 
placed  in  favorable 
conditions  for  the 
growth  of  germs,  will 
soon  spoil.  On  the 
other  hand,  heat  if 
continued  long 
enough  kills  bacte- 
ria; and  no  germs 
will  grow  in  foods 
thus  heated  pro- 
vided they  are  kept 
from  air  which  con- 
tains germs.  With  a 
knowledge  of  these 
facts  we  can  better 
understand  the  prin- 
ciples underlying  the 


use  of  the  ice  box, 
cold  storage,  and 
canning. 

Value  of  the  re- 
frigerator in  the 
home.  —  We  have 


Circulation  of  air  in  the  refrigerator.    What  foods  are 
placed  below  the  ice  chamber  ?    Why  ? 


seen  that  warm,  moist  air  helps  germs  to  grow,  and  decay 
to  take  place.  The  refrigerator  prevents  this  decay  by  sur- 
rounding foods  with  dry,  cold  air.  Left-overs  which  other- 
wise would  be  wasted  are  thus  saved  for  use,  and  foods 
and  drinks  are  made  more  palatable. 


HOW  TO  USE  THE  ICE  BOX  123 

Construction  of  the  refrigerator.  —  The  household  re- 
frigerator is  really  a  large  box  with  thick,  heat-insulating 
walls,  and  with  doors  or  covers  to  the  several  compart- 
ments inside.  There  is  always  one  chamber  for  the  ice, 
and  several  others  with  shelves  for  food.  All  of  the 
compartments  within  are  connected  by  air  ducts  or 
spaces,  so  that  there  is  a  free  circulation  of  air  through- 
out the  entire  refrigerator.  The  drainage  pipe  leads  to 
a  pan,  or  to  a  waste  pipe.  This  drainage  pipe  is  pro- 
tected by  a  trap  which  prevents  warm  air  from  coming 
in.  The  wall  is  of  much  importance;  one  of  the  best 
is  made  of  layers  suggested  in  the  diagram.  If  heat 
enters  this  wall,  it  must  go  through  all  of  these  insulating 
substances. 

How  to  use  the  ice  box.  —  When  air  comes  in  contact 
with  ice,  it  gives  up  heat  to  the  ice,  and  becomes  colder  and 
heavier,  and  sinks  to  the  bottom  of  the  ice  chamber. 
An  outlet  below  the  ice  allows  this  cold  air  to  pass  out  at 
one  side  to  the  bottom  part  of  the  refrigerator,  where  warm 
food  substances  give  off  their  heat  to  the  cold  air,  which  is 
warmed  and  gradually  rises,  passing  in  again  at  the  top 
of  the  ice  chamber.  Thus  we  have  a  circulation  of  air 
within  the  ice  box. 

The  warm  air,  returning  to  the  ice,  causes  some  of  it  to 
melt,  and  the  heat  is  thus  carried  off  in  the  water  which 
drips  out  into  a  drain  outside.  Since  most  foods  have  more 
or  less  odor,  we  must  place  those  which  give  off  the  most 
odor  at  the  top  of  the  ice  chest  where,  the  air  is  warmer, 
while  meats,  milk,  and  butter  should  be  placed  in  the 
coldest  part  of  the  ice  box,  where  they  will  not  take  the 
odor  from  other  things.  If  you  want  your  ice  box  to  be 
cold  inside,  do  not  cover  the  ice  with  newspapers  or  a  woolen 


124 


PURE   FOOD  IN  THE  HOME 


blanket.  If  you  desire  to  keep 
the  ice,  and  not  the  food,  then 
this  is  the  way  to  do  it. 

The  iceless  refrigerator. — An 
interesting  home  project  is  the 
making  of  an  iceless  refrigerator. 
Directions  may  be  found  in  the 
U.  S.  Dept.  of  Agriculture  pam- 
phlet, Food  Thrift  Series,  No.  4. 
The  principle  of  evaporation  and 
transfer  of  heat  from  the  inside 
to  the  outside  of  the  box  explains 
its  value.  Study  the  diagram 
and  see  how  it  might  be  usefully 
applied  to  your  own  home. 

Thermos  bottle.  —  The  ther- 
mos bottle,  as  a  study  of  the 
diagram  will  show,  is  another  applica- 
tion of  insulation.  It  is  essentially  a 
double  walled  bottle  or  one  bottle  in- 
side of  another,  with  a  vacuum  space 
between.  A  vacuum  is  a  better  insu- 
lator than  air.  The  inside  walls  of 
the  bottles  surrounding  the  vacuum 
are  mirrors.  They  reflect  radiant  heat 
energy  and  prevent  its  passage  across 
the  vacuum.  Thus  the  thermos  bot- 
tle keeps  cold  substances  cold,  and  hot 
substances  hot,  by  means  of  insulation. 
Canning  foods.  —  Canning  is  simply 
a  method  by  which  foods  are  boiled  to  kill  the  bacteria  in 
them  and  then  placed  in  vessels  into  which  no  more  bacteria 


The  iceless  refrigerator.  The  out- 
side canvas  dips  into  a  pan  of 
water  at  the  top  and  drains  into 
another  pan  at  the  bottom  of  the 
refrigerator.  (U.  S.  Dept.  Agri.) 


PASTEURIZATION  OF  MILK 


125 


Section  of  thermos  bottle. 
(After  Hoadley.) 


can  gain  entrance.  This  is  done 
usually  by  boiling  fruits  or  vege- 
tables, sometimes  with  sugar  or 
salt,  and  placing  them  immediately 
in  sterile  jars  and  then  sealing  them 
tightly.  They  may  also  be  canned 
by  simply  placing  food  uncooked 
but  clean  in  cans,  closing  the  cans, 
and  then  sterilizing  by  boiling  for 
a  considerable  period  of  time.  The 
United  States  Government,  De- 
partment of  Agriculture,  Farmers' 
Bulletin  No.  839  gives  full  direc- 
tions for  canning  by  this  last  method,  called  the  cold-pack 
process.  Some  vegetables  such  as  peas,  beans,  and  corn  are 
very  difficult  to  can,  probably  because  of  spores  of  bacteria 

which  are  attached  to  them,  and 
it  requires  a  longer  heating  to  kill 
the  spores.  Fruits,  on  the  other 
hand,  are  usually  much  easier  to 
sterilize.  The  main  thing  to  bear 
in  mind  is  to  have  the  jars  as  well 
as  the  material  that  goes  into 
them,  sterilized,  that  is,  absolutely 
free  from  all  living  matter.  This 
can  be  done  best  by  long  boiling. 
Pasteurization  of  milk.  —  Milk 
is  one  of  the  favorite  foods  of 
bacteria.  It  is  also  a  very  im- 
portant food  for  children,  and 
since  a  baby's  digestive  system 
is  easily  upset,  we  should  pro- 


Pasteurizing  apparatus,  an  arrange- 
ment by  which  milk  is  conven- 
iently heated  to  destroy  disease 
germs.  The  thermometer  tells 
the  degree  of  heat  used. 


126 


PURE   FOOD   IN  THE   HOME 


tect  it  by  having  the  milk  as  free  from  germs  as  possible. 
All  milk  contains  some  germs,  even  shortly  after  taken  from 
the  cow,  the  most  numerous  being  those  which  cause  milk 
to  sour.  To  kill  the  harmful  bacteria  and  not  injure  the 
milk,  a  method  known  as  pasteurization  is  used.  This  pro- 


A  model  kitchen. 

cess  is  named  after  the  great  French  scientist,  Louis 
Pasteur,  who  did  so  much  to  apply  his  knowledge  of  harm- 
ful germs  to  human  betterment.  By  this  method  milk  is 
heated  to  a  temperature  of  not  over  150  degrees  Fahrenheit 
for  a  period  of  ten  minutes  to  one  half  hour.  The  diagram 
at  the  bottom  of  page  125  shows  an  excellent  home  pas- 
teurization apparatus.  In  cities  most  milk  delivered  to 
the  home  has  been  pasteurized,  because  the  milk  is  some- 
times forty-eight  hours  old  before  it  is  delivered  to  cus- 
tomers. 


A  CLEAN  KITCHEN  NECESSARY 


127 


Flavors  in  foods.  —  Foods  frequently  get  a  large  part  of 
their  flavor  from  the  bacteria  which  live  in  them.  The  flavor 
of  butter,  the  "gamey  "  taste  of  certain  meats,  the  flavor  of 
sauerkraut,  are  due  to  the  work  of  bacteria.  Bacteria  have 
some  useful,  as  well  as  harmful,  effects  in  foods. 

A  clean  kitchen  necessary.  —  Since  foods  are  handled  in 
the  kitchen,  it  goes  without  saying  that  a  clean  kitchen 
will  go  a  long  way  to  pre- 
vent spoiling  of  foods.  This 
means  that  all  surfaces  in 
the  kitchen  should  be  washed 
frequently.  Why?  Tables 
and  shelves  should  be  cov- 
ered with  oil  cloth  or  some- 
thing which  can  be  wiped  off 
and  dried  quickly.  Wooden 
surfaces,  especially  when 
they  become  greasy,  make 
excellent  homes  for  bacteria. 
Remember  that  hands  must 


NUMBER  OF  BACTERIA  LEfT  ON  A- 
AfTER  DIFFERENT  METHOD?  OF  WASHING 


259,000 


i.  As  plate  leaves  table.    2.  Washed  in 


B£*r«,£J2- 


Was" 


be  kept  clean  when  handling 

foods.     Since  flies  carry  dis- 

ease  the  kitchen  should  be 

screened.     Dishes  should  be 

washed  clean  with  plenty  of 

soap   and   hot   water.     The  accompanying    diagram   will 

illustrate  how  the  clean  washing  of  dishes  helps  in  keeping 

bacteria  from  foods. 

An  excellent  method  of  drying  is  to  stack  the  dishes  on  the 
draining  board  and  then  to  pour  boiling  water  over  them. 
Why  is  this  better  than  drying  them  with  a  hand  towel  ?  Is  it 
a  good  plan  to  leave  the  dishes  to  drain  overnight  ?  Why  not  ? 


128 


PURE   FOOD   IN  THE  HOME 


Hints  on  the  use  of  this  score  card.  —  We  are  all  in- 
terested in  keeping  well  and  strong.  We  all  like  good 
things  to  eat,  too.  Study  the  conditions  in  your  home, 
suggested  by  each  item  in  the  score  card.  Be  fair  in  your 
marking.  The  purpose  is  not  to  see  who  can  get  the 
highest  score  but  to  show  each  one  of  you  just  what  con- 
ditions surround  you  and  to  suggest  those  things  which 
need  correction  the  most. 

SCORE  CARD.    PURE  FOOD  IN  MY  HOME 


MY  SCORE 

EXCELLENT 

FAIR 

VERY  POOR 

Tota.1 

CLEANLI- 

Closed   closet    for 

Closed      closet; 

No  closet  for  dishes 

NESS   IN 

dishes    —    Glass 

wooden  doors  (i) 

(o) 

THE   CARE 

doors  (2) 

OF   FOOD 

Dishes    scalded, 

Dishes    dried    with 

Dishes  not  scalded 

drained  dry  (2) 

clean  towel  (i) 

(o) 

Wash    hands    with 

Sometimes   remem- 

Never wash  hands 

soap    and    water 

ber       to       wash 

before     handling 

before     handling 

hands  (i) 

food  (o) 

food  (3) 

Kitchen  table,  floor, 

Table,     woodwork, 

Kitchen     table, 

woodwork,      and 

floor,    and    walls 

woodwork,   floor, 

walls  always  kept 

usually  clean  (i) 

and  walls  seldom 

clean  (3) 

clean  (o) 

REFRIG- 

Large    enough     to 

Too  small  (i) 

No  refrigerator  (o) 

ERATOR 

hold  all  food  (2) 

Enamel    or    porce- 

Galvanized iron  or 

Rough   or   cracked 

lain  lining,  easily 

zinc  interior  (i) 

interior  (o) 

cleaned  (2) 

Economical  of  ice, 

Wasteful  of  ice  (i) 

Does  not  keep  ice 

good    circulation 

or  food  ;   poor  in- 

(2) 

sulation  (o) 

Food        properly 

Food  in  part  prop- 

No   knowledge    of 

placed    to    show 
knowledge  of  con- 

erly placed.  Some 
foods     spoil     or 

convection     cur- 
rents shown  (o) 

vection    currents 

taste  (i) 

(2) 

Washed  thoroughly 
twice  a  week  (2) 

Washed  thoroughly 
once  a  week  (i) 

Washed  irregularly 
Has  odor  (o) 

STERILI- 

Left-overs     heated 

Some         left-overs 

No  left-overs  saved 

ZATION 
AND 

to   boiling   point 
to  prevent  spoil- 

thrown away  be- 
cause of  not  being 

(o) 

PASTEURI- 

ing (3) 

sterilized  (i) 

ZATION 

No    fruits    left    to 

Fruit     occasionally 

Fruit   often   spoils. 

spoil  (2) 

spoils  (i) 

not    cooked    and 

saved  (o) 

All   milk   left  ov?r 

Some  milk  scalded, 

No  milk  saved  (o) 

scalded  for  cook- 

some sours  and  is 

ing  (2) 

thrown  out  (i) 

Milk    for    children 

No    certified    milk 

No   pasteurized    or 

pasteurized       at 

but  town  or  city 

certified  milk  (o) 

home  or  certified 

supply     pasteur- 

milk used  (3) 

ized  (2) 

REFERENCE  BOOKS 


129 


SCORE    CARD.     PURE   FOOD   IN   MY   HOME  —  Continued 


MV  5 

)CORE 

EXCELLENT 

FAIR 

VTTPV  Pnrn? 

Total 

USE   OF 

Proper     knowledge 

Somo   food   wasted 

Much  food  wasted 

PRESERV- 

of use  of  preserv- 

because of  lack  of 

(o) 

ATIVES 

atives    shown. 

knowledge  (i) 

No  food  wasted 

(2) 

Salt   or   waterglass 

Salt   or   waterglass 

Salted     food     not 

used   in   preserv- 

sometimes    used 

used;     Eggs  not 

ing  foods  (2) 

in  preserving 

preserved  (o) 

food  (i) 

All    extra    supplies 
of  vegetables  and 

Part  of  extra  supply 
canned  (i) 

None  of  extra  sup- 
ply canned  (o) 

fruits  canned  (2) 

Sugar  used  in  pre- 

Some    fruits     and 

No  homemade  jel- 

serving fruits  (2) 

jellies  made,  but 

lies  or  preserves 

not  all  utilized  (i) 

(o) 

No    harmful     pre- 

Use   of     preserva- 

Preservatives other 

servatives      in 

tives     in     some 

than  salt,  sugar, 

bought  foods  (2) 

bought    food 

and     vinegar    in 

shown    by    label 

much    food    pur- 

d) 

chased  (o) 

PROTEC- 

Perishable  foods 

Perishable  foods 

Much       perishable 

TION   OF 

kept  cool  (2) 

sometimes     kept 

food  wasted  be- 

FOODS 

cool  (i) 

cause    not    kept 

cool  (o) 

Foods  kept  covered 

Foods      sometimes 

Foods  often  uncov- 

(2) 

covered  (i) 

ered  (o) 

Canned  goods  never 

Canned       goods 

Canned  goods  often 

left  in  cans  after 

sometimes  left  in 

left  in  cans  after 

they  are  opened 

cans  (i) 

opening  (o) 

All  foods  protected 

Insects    sometimes 

Insects     often     in 

from  insect  (2) 

get  in  foods  (i) 

food  (o) 

Fly  screens  in  win- 

Fly screens  in  win- 

No screens;    many 

dows;   no  flies  in 

dows  ;  a  few  flies 

flies  in  house  (o) 

house  (2) 

in  house  (i) 

GRAND 

rOTAL 

REFERENCE   BOOKS 

Allen,  Civics  and  Health,  Chapter  XXV  (For  teachers).     Ginn  and  Company. 
Broadhurst,  Home  and  Community  Hygiene,  Chapters  I,  III,  IV  (Teacher's  use). 

J.  B.  Lippincott  Co. 
Caldweil  and  Eikenberry,  Elements  of  General  Science,  Chapter  VIII.     Ginn  and 

Company. 

Clark.  An  Introduction  to  Science,  Chapters  IX,  XIV.     American  Book  Company 
Conn,  Bacteria,  Yeasts  and  Molds  of  the  Home.     Ginn  and  Company. 
Claycomb-  Petri  Dish  Projects.     School  Science  and  Mathematics,  April,  1918. 
The  Persistent  Delusion  of  Ptomaine  Poisoning.     Current  Opinion,  April,  1918. 
Hunter,  A  Civic  Biology,  Chapters  XI,  XXIV.    American  Book  Company. 
H.-WHIT.    CIV.    SCI.   IN  THE  HOME  —  Q 


130  PURE  FOOD   IN  THE  HOME 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapter  XI  (For  suggested  exper- 
imental work).  American  Book  Company. 

McNutt,  The  Modern  Milk  Problem  (For  teachers).     The  Macmillan  Company. 

Official  Handbook,  Boy  Scouts  of  America  (Questions  on  decay).  Doubleday,  Page 
and  Company. 

Public  Health  Service  Bulletin  56,  Milk  and  its  Relation  to  Public  Health. 

Ritchie,  Primer  of  Sanitation,  Chapter  XXX.     World  Book  Company. 

Milk,  U.  S.  Department  of  Labor,  Bulletin  35  —  Children's  Bureau. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  X.  Houghton 
Miffiin  Company. 

Vulte  and  Vanderbilt,  Food  Industries,  Chapter  VIII.  Chemical  Publishing 
Company. 

Weed,  Chemistry  in  the  Home,  Chapter  XXIV.    American  Book  Company. 

Wing,  Milk  and  Its  Products  (For  teachers).    The  Macmillan  Company. 


CHAPTER  VIII 

HOUSEHOLD  PESTS  AND  HOW  TO  FIGHT  THEM 

Problems.  —  i.  To  understand  what  harm  is  done  by 
household  pests. 

2.  To  learn  the  life  history  of  some  harmful  insects. 

3.  To  find  how  household  pests  can  be  exterminated. 

Experiment.  —  To  work  out  the  life  cycle  of  the  fly. 

Project  I.  —  To  EXTERMINATE  FLIES  FROM  MY  HOME. 

1.  Find  details  of  various  methods  of  getting  rid  of  flies.     Traps, 
tanglefoot,  poison  papers,  liquids,  and  powders. 

2.  Find  details  of  means  of  preventing  production  of  flies  which 
will  be  of  value  in  your  particular  place.     Care  of  breeding  places. 

3.  Make  a  plan  of  campaign  and  carry  it  out. 

4.  Make  a  complete  report  of  your  project.     State  to  what  ex- 
tent the  fly  nuisance  has  been  abated. 

Suggested  Projects. 

1.  TO  RID  THE  HOUSE  OF  RATS  AND  MICE. 

2.  TO     WORK     OUT     METHODS     OF     FIGHTING     OTHER    HOUSEHOLD 
PESTS. 

3.  TO   PREPARE    PROPER    CONTAINERS,    AND    STORAGE    SPACE    FOR 
CLOTHES,  AND  TO  KEEP  WINTER  CLOTHING  OVER  SUMMER  SAFE  FROM 
MOTHS. 

What  household  pests  do.  —  What  a  pleasant  place  the 
world  would  be  to  live  in  if  it  were  not  for  the  flies  and  mos- 
quitoes which  annoy  us,  fleas  and  bedbugs  which  bite  us, 


132    HOUSEHOLD   PESTS  AND  HOW  TO  FIGHT  THEM 

weevils  and  roaches  to  get  into  our  foods,  and  rats  and  mice 
to  destroy  our  homes  and  damage  our  plants  and  crops. 

Estimates  made  by  the  United  States  Department  of 
Agriculture  show  that  over  a  billion  dollars'  worth  of 
damage  is  done  each  year  to  crops  and  other  property  in 
this  country  by  insects  alone.  An  estimate  is  made  that 
at  least  a  million  dollars'  damage  a  year  is  done  by  rats  in 
the  city  of  Pittsburgh  alone.  But  aside  from  these  losses 
the  untold  suffering  and  the  many  unnecessary  deaths 
caused  by  diseases  which  are  carried  by  insects  and  other 


Follow  the  fly.    What  happens  ? 

animals,  should  cause  us  to  spend  thought  and  time  in 
making  homes  as  free  as  possible  from  these  household 
pests.  Almost  every  day  scientists  discover  some  new 
relation  between  insects  and  diseases.  Many  infectious 
diseases  depend  in  part,  at  least,  upon  insects  as  carriers. 
The  fly  which  to-day  puts  its  dirty  feet  in  baby's  cup 
of  milk  yesterday  lived  in  a  manure  heap,  and  on  the 
way  here  may  have  stopped  in  a  privy.  This  is  not  nice 
to  think  about,  but  it  is  fact,  nevertheless,  and  every  think- 
ing boy  and  girl  should  realize  these  things. 

The  house  fly  in  relation  to  our  home.  —  It  is  estimated 
that  while  snakes  kill  perhaps  two  or  three  people  every 
year  in  the  United  States,  house  flies  are  responsible  for 


THE  HOUSE  FLY  IN  RELATION  TO  OUR  HOME    133 


the  deaths  of  about  100,000  people.  This  is  due  to  the  filthy 
habits  of  flies.  Probably  most  of  the  dysentery  and  sum- 
mer complaint,  especially  of  babies,  is  due  directly  to  flies, 
for  they  carry  directly  to  baby's  milk  on  their  legs  or  bodies 
germs  which  they  have 
taken  from  some  other 
sick  baby  or  person  hav- 
ing the  disease. 

Typhoid  fever,  a  well- 
known  disease,  responsi- 
ble for  a  great  many 
deaths,  especially  in 
country  districts,  is  un- 
doubtedly largely  spread 
by  means  of  flies.  A 
study  of  the  accompany- 
ing diagram  will  show 
clearly  that  the  warm 
weather,  spread  of  ty- 
phoid, and  diarrhoea  are  coincident  with  fly  time.  A 
knowledge  of  the  life  history  of  the  fly  will  help  us  to 
combat  the  pest. 

Experiment.  —  To  work  out  the  life  history  of  the  fly. 

Materials:  A  small  wire  cage.     A  piece  of  stale  meat. 

Method:  Leave  the  meat  out  in  the  open  where  there  are  plenty  of  flies 
until  you  can  see  fly  eggs,  then  cover  it  with  a  wire  cage  and  keep  it 
in  a  warm  place. 

Observation:  Look  at  it  every  few  days.  What  different  stages  follow 
the  egg  stage  ?  How  long  does  it  take  each  stage  to  develop  ?  Do  you 
think  temperature  would  have  any  effect  on  the  rapidity  of  develop- 
ment? 

Conclusion:  What  is  the  life  cycle  of  the  fly? 

Application:  Does  this  experiment  suggest  any  method  of  control  of  the 
number  of  flies  about  the  house  ? 


There  were  329  cases  of  typhoid  in  Jacksonville, 
Florida,  in  1910;  158  in  1911;  and  87  in  the 
first  10  months  of  1912.  During  the  winter  of 
1910-1911,  80  to  85  %  of  the  outdoor  toilets 
were  made  flyproof .  How  would  you  account 
for  the  great  decrease  in  cases  of  typhoid  in- 
dicated in  1911  and  1912  ? 


134    HOUSEHOLD   PESTS  AND  HOW  TO   FIGHT  THEM 


How  to  get  rid  of  flies.  —  In  order  to  rid  our  houses  of 
these  pests  it  is  necessary  to  know  something  about  the 
habits  of  flies.  Flies  commonly  breed  in  manure,  but 
sometimes  in  garbage  which  has  been  allowed  to  stand 
in  uncovered  cans  and  in  rotting  masses  of  paper  and  other 
rubbish,  provided  it  is  moist.  A  fly  does  not  take  more 
than  ten  days  to  complete  its  life  history  in  warm  weather. 
The  eggs  hatch  in  about  eight  hours  into  maggots. 

These  whitish 
wormlike  animals 
burrow  into  the 
manure  pile  and 
there  after  six  or 
seven  days  become 
brown  pupae,  and 
hatch  out  three 
days  later  as  adult 
flies.  Since  an 
adult  fly  lays 
about  one  hun- 
dred and  fifty  eggs 
at  a  time,  and  about  one  half  of  all  flies  are  females,  it  is  not 
difficult  to  estimate  how  many  flies  might  come  from  one  pair 
in  a  season.  Hodge  has  estimated  that  within  three  months 
the  offspring  from  one  fly  would  amount  to  143,675  bushels 
of  flies.  If  these  figures  are  correct,  it  is  evident  that 
"  swatting  the  fly  "  or  using  screens  will  not  do  much  good 
unless  the  flies  are  "  swatted  "  early  in  the  season  when  there 
are  not  very  many  which  have  lived  through  the  winter. 
Evidently  the  best  things  to  do  are  to  destroy  the  breeding 
places  of  flies  and  to  trap  as  many  as  possible.  All  manure 
heaps  should  be  worked  over  and  scattered  at  least  once 


Life  history  of  house  flies,  showing  from  left  to  right  the 
eggs,  larvae,  pupae,  and  adult  flies.  (Photograph  about 
natural  size,  by  Overton.) 


MOSQUITOES 


135 


A  fly  trap. 


every  ten  days  so  that  the  flies  cannot  have  a  chance  to 
breed.  Garbage  and  any  material  that  might  form  a  breed- 
ing place  should  be  carefully  removed  within  the  ten-day 
period.  One  of  the  best  baits  for  flies  is  made  by  adding 
to  a  pint  of  milk  and 
water  two  tablespoon- 
fuls  of  formaldehyde. 
Place  a  piece  of  bread 
in  a  shallow  dish  and 
almost  cover  it  with 
the  poisonous  dose.  An 
excellent  home  project 
would  be  the  manu- 
facture of  an  efficient 
fly  trap.  The  United 
States  Government  bulletins,  for  example,  Farmers'  Bulle- 
tin No.  927,  or  Hodge's  Nature  Study  and  Life  give  de- 
scriptions of  excellent  traps. 

In  addition  to  the  house  fly,  many  other  flies,  as  the 
stable  fly,  the  fruit  fly,  and  the  black  fly,  cause  us  great 
annoyance,  and  some  are  believed  to  carry  disease. 

Mosquitoes.  —  We  have  all  at  one  time  or  another 
been  annoyed  by  mosquitoes.  They  render  some  parts 
of  cities  and  towns  unfit  for  human  residence,  not  only 
because  of  their  bite,  but  because  they  carry  malaria. 
The  old  belief  that  malaria  was  caused  by  bad  air  has 
long  been  exploded,  for  experiments  have  proved  that  a 
certain  kind  of  mosquito,  the  anopheles,  is  responsible  for 
carrying  this  disease.  A  careful  study  of  the  diagram  will 
show  how  we  can  distinguish  between  the  harmless  culex 
and  the  harmful  anopheles.  The  harmful  one,  as  you 
notice,  stands  with  its  body  oblique  while  the  culex  holds 


136    HOUSEHOLD   PESTS  AND   HOW  TO  FIGHT  THEM 


its  body  parallel  to  the  surface.  Mosquitoes  breed  in  water, 
and  unfortunately  for  us,  rain  barrels,  roof  gutters,  or  any 
place  where  water  remains  for  two  weeks  or  more  can 
raise  a  large  number  of  these  nuisances.  Their  life  his- 
tory can  be  understood  by  studying  the  diagram  be- 
low. The  common  culex,  the  house  mosquito,  lays  from 

two  hundred  to  four 
hundred  eggs.  The 
little  wigglers  which 
come  from  the  eggs  live 
in  water,  obtaining  their 
oxygen  through  a  long 
tube  which  sticks  out  of 
the  water  when  they  go 
to  the  surface  to  breathe. 
It  takes  from  two  to 
three  weeks  for  the  mos- 
quito to  complete  its  life 
from  the  egg  to  the  adult. 
Since  mosquitoes  live 
during  this  time  under 
water,  and  since  they 
must  come  to  the  surface 
to  get  air,  a  simple  way 
to  destroy  them  by  pre- 
venting their  breathing 
is  to  pour  oil  over  the  standing  water  in  which  they  lay 
their  eggs.  Sometimes  it  is  necessary  to  drain  swampy 
areas  where  standing  water  makes  breeding  places,  and 
many  households  have  been  relieved  from  the  plague  of 
mosquitoes  by  the  simple  removal  of  empty  cans  or  bar- 
rels which  might  hold  water.  Why  not  make  a  survey  of 


The  four  stages  in  the  life  history.  Read  from 
top  to  bottom  as  follows:  egg,  larvae  (wig- 
glers), pupae,  adult.  At  the  left  is  seen  the 
culex;  at  the  right,  the  harmful  anopheles. 


LICE  137 

your  own  house  and  grounds  and  make  sure  that  no  stand- 
ing water  is  near,  for  mosquitoes  rarely  fly  more  than  a 
few  hundred  yards  from  where  they  hatch.  The  introduc- 
tion of  goldfish,  sticklebacks,  or  other  small  fish  will  soon 
rid  ponds  of  mosquitoes. 

Yellow  fever,  which  at  one  time  was  a  terrible  menace  in 
this  country,  is  carried  by  another  kind  of  mosquito.  We 
will  discuss  this  more  fully  in  "  Civic  Science  in  the  Com- 
munity." 

Fleas.  —  The  ordinary  dog  and  cat  flea  should  always  be 
considered  a  menace  to  health,  for  it  may  carry  bubonic 
plague  and  infect  people  with  it. 
Plague  is  a  disease  of  rats,  but  is 
spread  by  fleas  which  live  upon  them. 
Fortunately  this  disease  is  not  prev- 
alent in  this  country,  although  in  Flea  which  traiTsmits  bubonic 
some  parts  of  the  world,  particularly  plague  from  rat  to  man. 
in  China,  it  is  killing  many  thousands  of  people  yearly. 
Fleas  flourish  in  dust,  under  carpets,  in  cracks,  and  par- 
ticularly where  dogs  and  cats  sleep.  Mats  on  which  these 
animals  sleep  should  be  constantly  dusted  and  cleaned, 

and  benzene  or  pyrethrum  powder  may  be  used 

to  fight  the  pests. 
Lice.  —  Lice  are  wingless  insects  which  have 

come  into  prominence  during  the  World  War. 

The  body  louse  is  the  "  cootie  "  of  the  soldier. 

It  becomes  a  very  serious  pest  to  those  obliged 

to  live  in  dirty  surroundings,  and  can  be 
The  "cootie."  eradicated  only  by  having  the  clothes  sterilized 
and  by  treatment  of  the  body  with  ointments.  The  head 
louse  sometimes  found  in  the  heads  of  school  children  is  very 
annoying  and  hard  to  get  rid  of.  The  "  nits  "  or  eggs  are 


138    HOUSEHOLD   PESTS  AND   HOW  TO   FIGHT  THEM 

attached  to  hairs,  and  can  only  be  removed  after  thoroughly 
washing  and  combing.  The  application  of  larkspur  is 
found  to  kill  the  pests. 

Bedbugs.  —  Although  the  bedbug  is  usually  found  in 
dirty  homes,  it  may  come  from  outside  into  clean  houses. 
Bedbugs  move  around  only  at  night,  and 
their  very  flat  bodies  get  into  small  crevices, 
especially  along  wall  boards  and  in  wooden 
beds,  where  they  may  become  very  annoy- 
ing. They  are  much  more  active  in  hot 
The  bedbug.  weather  than  in  cold.  While  the  bite  is  not 
serious,  it  is  believed  sometimes  to  carry  diseases.  To  rid 
the  house  of  bedbugs  it  is  necessary  to  clean  all  furniture 
and  woodwork  thoroughly.  Every  crack  in  the  furniture 
and  floors  should  be  treated  with  formalin  or  an  insecticide 
made  particularly  for  destroying  this  pest. 

Insects  which  attack  food.  —  Some  household  pests 
are  attracted  to  the  house  by  our  food.  Cockroaches  are 
found  usually  around  sinks  or  in  food  closets.  They  eat 
almost  anything,  and  are  apt  to  be  a  great  nuisance,  al- 
though the  damage  they  do  is  not  very  great. 
They  are  difficult  to  get  rid  of,  as  every  house- 
wife knows.  They  may  be  poisoned  by  feed- 
ing them  a  mixture  of  sugar  and  powdered 
borax.  All  cracks  and  crevices  where  they 
hide  should  be  sprayed  with  bisulphide  of  car- 
bon which  will  kill  them.  They  may  be 

.  11.  The  cockroach. 

trapped  by  plating  food  in  a  deep  dish  into 

which  they  may  crawl  by  means  of  sticks,  but  from  which 

they  cannot  get  out. 

Ants  also  are  very  troublesome,  as  they  destroy  many 
kinds  of  foods.     The  best  way  to  rid  the  house  of  them  is. 


INSECTS  WHICH  ATTACK  CLOTHES 


139 


The  ant. 


to  find  their  nest  and  pour  into  it  a  few  ounces  of  carbon 

bisulphide.     (This  is  a  dangerous  liquid   to  handle,  but 

is  less  explosive  than  gasoline.)     Colonies 

of  ants  in  the  house  may  be  treated  also 

with  gasoline  or  boiling  water,  and  the  ants 

may  be  kept  from  getting  into  the  house 

by  placing  a  border  of  some  substance  that 

they  do  not  like,  such  as  powdered  borax,  on 

the  threshold.     Sulphonaphthol  is  another 

efficient  means  of  ridding  the  house  of  ants. 

Insects  which  attack  clothes.  —  Two  insects,  clothes 
moths  and  carpet  beetles  (Buffalo  moth  or  Buffalo  bug), 
are  pests  which  do  much  damage  to  stored  materials,  espe- 
cially our  clothes  and  rugs.  The  young,  or  larvae,  feed 
on  the  woolen  and  fur  of  the  clothes,  and  do  much  damage 
in  this  way.  If  these  materials  are  well  dusted  and  allowed 
to  hang  outside  in  the  sun  a  few  hours  before  putting  them 
away  for  the  summer,  and  then  packed  into  tight  boxes  or 
bags,  they  will  not  be  troubled  by  moths.  Moth  balls  and 

camphor  keep  out 
the  insects,  but  do 
not  kill  them,  so  that 
if  clothes  are  put 
away  with  the  in- 
sect in  them  they 
will  not  be  pro- 
tected. The  carpet 
beetle  can  be  fought 
It  feeds  on  carpets 


The  clothes  moth,     i,  eggs;  2,  larva;  3,  pupa; 
4,  adult. 


in  the  same  way  as  the  clothes  moth, 
and  other  goods  stored  away. 

Household  insects  may  be  grouped   according   to   the 
damage  they  do.     The  following  experiment  is  suggested 


140    HOUSEHOLD   PESTS  AND   HOW  TO   FIGHT  THEM 


that  you  may  see  which  insects  should  be  grouped  to- 
gether : 

Experiment.  —  To  classify  the  insects  of  the  home  according  to  the  harm 

they  do. 

Make  a  list  of  all  the  household  insect  pests  you  can  find  out  about. 
List  these  under  the  suggested  headings  according  to  the  harm  they  do. 
Possibly  some  one  insect  will  need  to  be  listed  in  more  than  one  column. 


DISEASE  CARRIERS 

EATS  AND  DESTROYS 
FOODS 

ANNOYS  AND  BITES 

DESTROYS  TEXTILES 
AND  CLOTHING 

The  house  rat.  —  David  Lanz  of  the  Department  of 
Agriculture  calls  the  rat  the  worst  mammalian  pest 
known  to  man.  Not  only  do  they  do  many  million  dollars' 
damage  to  grain  stored  in  barns  but  they  kill  many 
young  chicks  and  destroy  a  great  number  of  eggs.  They 
have  been  estimated  to  do  $200,000,000  damage  in  the 
United  States  every  year.  Buildings  are  damaged,  water 
pipes  gnawed,  and  buildings  flooded.  Many  fires  are  caused 
by  rats  gnawing  off  the  insulation  of  electric  wires  and  by 
setting  off  matches  which  they  have  taken  to  their  nests. 
In  addition  to  this,  rats  are  responsible  for  killing  millions 
of  people  in  India  and  elsewhere  lately  by  carrying  the 
germs  of  the  bubonic  plague,  the  "  Black  Death  "  of  the 
Middle  Ages. 

One  of  the  practical  projects  a  boy  can  work  out  is  to  lay 
plans  for  the  trapping  of  rats  or  killing  them  by  means  of 
poison.  One  must  remember  that  poisons  are  dangerous 
to  handle  and  that  rats  and  mice  are  cunning,  so  that  it 
takes  constant  and  careful  work  in  order  to  finally  rid  the 


USE  OF  THE   SCORE   CARD 


141 


house  or  barn  of  these  destructive  pests.     Concrete  con- 
struction which  is  rat  proof  is  one  of  the  latest  and  best 


How  the  house  rat  does  damage.     (Photo  of  group  in  American  Museum  of  Natural 

History.) 

methods  of  preventing  rats  from  doing  damage  in  the 
home.  The  best  proof  that  this  chapter  has  not  been 
written  in  vain  will  be  the  home  work  of  those  who  read 
it.  Let  us  all  work  together  to  make  our  homes  safer 
and  better  places  in  which  to  live. 

Use  of  the  score  card.  —  While  it  is  not  always  pleasant 
to  admit  that  things  are  not  as  they  should  be,  yet  that 
is  a  good  way  to  begin  and  improvements  are  sure  to  fol- 
low. If  home  conditions  show  up  badly  in  this  card,  each 
boy  and  girl  should  go  to  work  at  once  to  make  them 
better.  Naturally  you  need  not  show  the  details  of  this 
card  to  any  one,  although  your  total  score  might  be  given. 


142    HOUSEHOLD   PESTS   AND   HOW   TO   FIGHT  THEM 


SCORE  CARD.    HOUSEHOLD  PESTS 


MY 

SCORE 

EXCELLENT 

FAIR 

VERY  POOR 

TOTAL 

FLIES 

No  manure  piles  (2) 

Manure   pilrj   pro- 
tected (i) 

Manure  piles  never 
disinfected  (o) 

Garbage   pail   with 

Garbage  pails  loose 

Garbage    pails     no 

tight  cover  (i) 
Garbage  pail  scald- 

covers (5) 
Garbage  pails  scald- 

cover (o) 
Garbage  pails  scald- 

ed twice  a  week 

ed  once  a  week 

ed      infrequently 

in  hot  weather  (i) 

in  hot  weather  (i) 

(o) 

No  outdoor  privies 

Outdoor         privies 

Privies  not  screened 

(2) 

well  screened  (i) 

(o) 

No  decaying  refuse 

Decaying  refuse  in 

Yards    with    much 

in  yard  (2) 

yard  occasionally 

refuse  (o) 

(i) 

All       windows 

Kitchen      windows 

No     windows 

screened  (i) 

screened  (5) 

screened  (o) 

Fly    traps    or    poi- 

Fly   traps    or    poi- 

No   traps    or    poi- 

sons and  swatters 

sons  or  swatters 

sons;        swatters 

(i) 

(any  two)  (J) 

only  used  (o) 

No  culex  (2) 

Very  few  culex  (i) 

Many  culex  (o) 

MOSQUI- 

No anopheles  (2) 

Very  few  anopheles 

Many  anopheles  (o) 

TOES 

d) 

No  breeding  places 

Breeding  places  not 

Breeding   places 

of  any  kind  (4) 

near  home  (2) 

near  home  (o) 

All  standing  water 

Standing  water  not 

oiled  regularly  in- 
cluding rain  bar- 

regularly oiled  (o) 

rels  (i) 

No    mosquitoes    in 

Mosquitoes  rare  in 

Many     mosquitoes 

house  (2) 

house  (i) 

in  house  at  night 

(o) 

BODY 

No  fleas  on  cat  or 

Fleas  on  cat  or  dog 

Fleas  in  carpets  or 

PESTS 

dog  in  house  (3) 

not     in     rooms. 

rugs.        Children 

Pets  washed  fre- 

often     bitten. 

quently  (2) 

Dog  or    cat  not 

washed  (o) 

No  bedbugs  (3) 

Bedbugs      infre- 

Bedbugs    frequent. 

quently      found. 
Insecticide    used 

Insecticide      not 
used  (o) 

frequently  (2) 

No  head  lice  (3) 

Children    rarely 

Children  frequently 

have  head  lice  or 

have  head  lice  or 

nits.     Treatment 

nits  (o) 

given   frequently 

(i) 

No      other      body 

Other  body  pests 

Other    body    pests 

pests  (i) 

sometimes  found 

frequent.      Dirty 

(i) 

conditions        o  f 

clothes    or    body 

(o) 

FOOD 

No  cockroaches  or 

Roaches    or    water 

Roaches  and  water 

AND 

water  bugs  (2) 

bugs    infrequent. 

bugs  frequent  ; 

CLOTHES 
PESTS 

Constant  care  ex- 
ercised.    Insecti- 

sink dirty;    food 
left  around  kitch- 

cides used  (i) 

en  ;    no     insecti- 

' 

cides  used  (o) 

No  ants  (2) 

Ants  sometimes  in 

Ants        numerous  ; 

pantries;    not  in 

much        food 

foods.        Insecti- 

spoiled by  them 

cides  used  (i) 

(o) 

REFERENCE  BOOKS 


143 


SCORE    CARD.     HOUSEHOLD    PESTS  —  Continued 


MY  S 

CORE 

T^Yr*1?T  T  T?MT 

FAIR 

Wuv    POOP 

TOTAL 

FOOD 

No  weevils  or  other 

Other    insects    de- 

Much food  thrown 

AND 

f  o  o  d-destroying 

structive  to  foods 

out    because    of 

CLOTHES 

insect  (2) 

sometimes  found 

weevils   or   other 

PESTS 

00 

insects.     No  care 

taken  (o) 

No    clothes    moths 

Clothes  moths  and 

Clothes    moths    or 

or  Buffalo  moths. 

Buffalo  moths 

Buffalo        moths 

All      precautions 

do         infrequent 

do  much  damage 

taken  (2) 

damage.    Clothes 

(o) 

well  cleaned  and 

put    away    with 

No     other     insect 

proper  care  (i) 
Other   pests   some- 

Other   pests    com- 

pests (2) 

times  seen  (i) 

mon  (o) 

RATS 

No    rats   in    house 

Rats     infrequently 

Much    damage    by 

AND 

or  barn  (6) 

seen;  little  dam- 

rats (o) 

MICE 

age  done  (i) 

No  mice  in  house 

Mice     infrequently 

Much    damage    by 

or  barn  (4) 

seen  ;   little  dam- 

mice (o) 

age  done  (i) 

Dog    and    cat    (i) 

No  dog  or  cat  (o) 

Traps     or    poisons 

No    traps    or    poi- 

used (i) 

sons  used  (o) 

Concrete  construc- 

No   concrete    con- 

tion (2) 

struction    or    tin 

to  cover  holes  (o) 

GRAND 

roTAL 

REFERENCE   BOOKS 

Broadhurst,  Home  and  Community  Hygiene,  Chapter  IX  (For  teachers).     J.  B. 

Lippincott  Company. 

Caldwell  and  Eikenberry,  General  Science,  Chapter  XX.     Ginn  and  Company. 
Doane,  Insects  and  Disease.     Henry  Holt  and  Company. 

Headier,  Effective  Methods  of  Fly  Control.     Sci.  Amer.  Supplement,  March  9,  1918. 
Headier,  The  Mosquito  Question.     Scientific  American   Supplement,  April  6,  1918. 
Herrick,  Insects  Injurious  to  the  Household.     The  Macmillan  Company. 
Hodge  and  Dawson,  Civic  Biology,  Chapters  X,  XI,   XIII,  XVIII  (Good).      Ginn 

and  Company. 

Hodge,  Nature  Study  and  Life.     Ginn  and  Company. 
Hunter,  A  Civic  Biology,  Chapter  XV.     American  Book  Company. 
Hunter,   Laboratory   Problems  in   Civic  Biology,    Chapter  XV.      American    Book 

Company. 

Kellogg,  American  Insects  (For  teachers).     Henry  Holt  and  Company. 
Kellogg  and  Doane,  Economic  Zoology  and  Entomology,    Chapters   XXX,  XXXI. 

Henry  Holt  and  Company. 

Ritchie,  Primer  of  Sanitation,  Chapter  XXIX.     World  Book  Company. 
Smith  and  Jewett,  Introduction  to  the  Study  of  Science,  Chapter  XII.     The  Macmillan 

Company. 


CHAPTER  IX 
HOW  WASTES  ARE  REMOVED  FROM  THE  HOME 

Problems.  —  i.  To  understand  how  wastes  are  removed 
from  the  body. 

2.  To  understand  the  system  of  waste  removal  needed  for 
the  home. 

3.  To  learn  how  the  various  plumbing  fixtures  work. 

4.  To  see  how  a  septic  tank  does  its  work. 

Experiments.  —  i.   To  see  how  a  siphon  works. 
2.   To  understand  how  a  flush  tank  works. 

Project  I.  —  To  PREPARE  MYSELF  TO  KEEP  THE  HOME  PLUMBING 

SYSTEM  IN  ORDER. 

This  involves  a  thorough  study  of  the  devices,  piping,  etc.  in  the 
home.  Diagrams  should  be  made  of  pipe  systems  showing  valves 
and  cut-offs,  etc.,  and  of  individual  devices,  as  traps,  bowls,  toilets, 
flush  tank,  and  faucets. 

Study  the  devices  seen  at  plumbers.  Talk  with  men  who  know 
how  these  devices  work.  Find  out  how  to  remedy  a  clogged  sink  drain, 
toilet,  and  wash  bowl  drain.  Learn  what  to  do  when  pipes  are  frozen 
and  when  a  large  leak  occurs,  and  how  to  repair  your  faucets.  Be 
sure  you  know  how  to  shut  off  water,  gas,  and  electricity  from  the 
entire  house. 

A  collection  of  pictures  of  plumbing  devices  cut  from  magazines 
and  described  in  your  own  words  will  make  a  splendid  section  in  your 
final  report  of  this  project. 

144 


HOW  WASTES  ARE  REMOVED  FROM  THE  BODY    145 


How  wastes  are 
removed  from  the 
human  body.  —  We 
have  seen  that  the 
human  body  uses 
foods  wherever  work 
is  done  in  it.  After 
the  food  is  digested 
in  the  food  tube  it 
is  absorbed  by  the 
blood  which  carries 
it  through  a  system 
of  pipes  called  veins 
to  a  pumping  station 
called  the  heart. 
This  is  a  double 
station ;  the  left  side 
of  it  forces  the  blood 


The  upper  cavities  in  the  heart  are  called  auricles  (right 
or  left),  the  lower,  the  ventricles  (right  or  left). 
Follow  the  arrows.  In  what  respect  is  the  heart 
like  a  force  pump  ? 


through  the  arteries  (see  diagram)  to  all  parts  of  the  body, 
while  the  right  side  pumps  blood  to  the  lungs.     Here,  as 

we  have  seen  before, 

1" 


VCS5K, 


I 


jalf 

LYMPH  SP/teiFV 
^"'1 


TUBB 


The  exchange  between  blood  and  the  cells  of  the  body.   Called 
H.-WHIT.   CIV.   SCI.   IN   THE   HOME  —  IO 


it  gives  up  carbon 
dioxide,  and  receives 
its  burden  of  oxygen. 
Before  the  blood 
reaches  the  cells,  the 
little  units  of  building 
material  of  which  the 
body  is  composed,  the 
vessels  containing  it 
divide  into  tiny  tubes 
capillaries. 


146    HOW   WASTES   ARE   REMOVED    FROM   THE   HOME 

The  liquid  food  soaks  through  the  thin  walls  of  the  capil- 
laries and  bathes  the  cells  so  that  they  are  continually 
supplied  with  food.  In  the  cells  the  food  is  oxidized  and 
energy  is  released.  Some  of  the  food  containing  nitrogen 
is  used  to  build  tissue  and  repair  the  body.  Nitrogen 
does  not  unite  easily  with  oxygen,  and  hence  a  consider- 
able amount  of  nitrogenous  material  must  be  passed  from 
the  body  as  waste.  This  nitrogenous  waste,  along  with 
other  waste  materials,  is  passed  out  from  the  cells  into  the 
lymph  spaces,  then  into  the  lymph  tubes,  and  ultimately 
gets  into  the  blood  again,  this  time  being  carried  through 
veins,  which  are  tubes  leading  toward  the  heart.  Wastes 
containing  nitrogen  are  finally  collected  by  the  kidneys,  from 
which  organ  they  are  passed  out  of  the  body  in  the  urine. 
Through  the  food  tube,  other  wastes  and  material  which 
cannot  be  digested  are  passed  out  in  a  partly  decayed  con- 
dition from  the  body.  This  work  of  decay  is  carried  on  by 
means  of  millions  of  bacteria  which  live  in  the  lower  part  of 
the  food  tube. 

Why  we  need  a  system  to  remove  wastes  from  the  home. 
—  All  body  wastes  from  the  home  as  well  as  garbage,  used 
water,  and  the  like  must  be  removed  from  our  homes  and 
put  where  they  cannot  do  any  harm  to  others.  Wastes  from 
the  body  contain  bacteria,  possibly  some  harmful  ones.  If 
we  were  alone  in  the  world  we  could  afford  to  be  selfish,  but 
when  we  are  living  where  there  are  many  other  people,  we 
cannot  do  anything  which  might  do  harm  to  others.  Open 
privies  to  which  flies  can  go  might  be  the  means  of  spreading 
disease  among  one's  own  brothers  and  sisters.  Garbage 
thrown  out  and  left  to  decay  may  mean  millions  of  flies 
for  you  and  your  neighbors.  Water  and  wastes  from  "the 
kitchen  sink  allowed  to  form  a  dirty,  smelling  pool  outside 


THE  NEED  OF  SANITARY  PLUMBING  147 

may  become  the  breeding  place  of  insects  as  well  as  a  place 
of  foul  odors.  The  purpose  of  this  chapter  is  to  point  out 
some  of  the  means  by  which  sewage  is  removed  from  the 
home  and  rendered  harmless  to  others.  We  must  remember 
that  sewage  or  material  containing  wastes  from  the  body 
substances  is  very  dangerous  to  health.  It  has  been 
shown  many  times  that  as  a  result  of  carelessness,  germs 
from  sewage  pass  into  the  drinking  water  or  get  on  the 
food.  It  is  necessary,  therefore,  that  sewage  everywhere, 
in  cities  as  well  as  the  country,  be  properly  disposed  of 
else  it  becomes  a  menace  to  health.  In  1854  there  was 
a  great  outbreak  of  Asiatic  cholera  in  London.  Some  parts 
of  the  city  were  stricken  much  more  than  others.  In  those 
clays  people  got  their  water  from  wells,  and  the  Broad  Street 
pump  had  such  a  reputation  for  clean,  sparkling  water, 
that  people  from  blocks  away  went  to  it  for  their  drinking 
water.  It  was  found,  however,  that  one  of  the  greatest 
outbreaks  of  cholera  was  among  people  taking  water  from 
this  well,  so  the  health  authorities  investigated  the  condi- 
tions there.  Imagine  their  horror  to  find  the  well  water 
separated  by  only  a  single  layer  of  old  worn-out  bricks 
from  a  cesspool  which  received  the  waste  materials  from 
many  cholera  patients.  As  cholera  is  a  disease  of  the  in- 
testines or  bowels  millions  of  germs  were  being  placed  in 
that  well  water  every  day.  After  the  well  was  closed  to  the 
public,  the  epidemic  subsided  in  that  part  of  the  city.  This 
is  only  one  instance  among  many  where  germs  in  the  water 
supply  have  done  untold  harm. 

The  need  of  sanitary  plumbing.  —  In  these  days  it  is 
hardly  necessary  for  people  to  have  outdoor  insanitary 
privies.  If  an  outdoor  privy  is  necessary,  then  all  parts 
should  be  carefully  screened  to  prevent  flies  from  getting 


148    HOW  WASTES  ARE  REMOVED   FROM  THE  HOME 


in,  and  the  lids  of  the  seats  should  be  close-fitting.  Earth 
mixed  with  lime  should  be  used  constantly  to  keep  the  waste 
material  in  the  receiving  vault  covered  so  that  flies  cannot 
get  to  it.  In  most  homes  nowadays  it  is  quite  possible 
to  have  indoor  toilets  and  pass  the  waste  material  along 
with  the  kitchen  and  other  wastes  into  an  underground 

sewer  in  cities  and 
into  cesspools  or 
septic  tanks  in  the 
country. 

The  modern  bath- 
room.— Most  houses 
nowadays  have  a 
warm  indoor  bath- 
room, furnished  with 
all  the  fixtures  shown 
in  the  illustration ;  a 
washbasin,  bathtub, 
mirror,  cupboard, 
towel  racks,  stool, 
and  toilet.  Not  very 
many  years  ago  it 
was  thought  proper 
to  cover  all  the 
plumbing  with 
wood,  but  this  is  insanitary,  because  it  makes  an  excellent 
place  for  germs  to  lodge  and  grow.  Now  we  find  bath- 
rooms furnished  with  one-piece  sanitary  bowls,  and  tubs 
made  either  of  porcelain  or  metal,  everything  raised  from 
the  floor,  with  all  parts  easy  to  get  at  in  case  of  repair. 
A  tub  with  cold  water  at  least  is  an  essential  part  of  a  bath- 
room, and  a  shower  bath  if  the  water  supply  is  sufficient, 


A  modern  bathroom. 


THE  MODERN  BATHROOM 


149 


Snr\          /*•'  SETS 


adds  much  pleasure  to  the  daily  life.  A  little  knowledge  of 
a  few  scientific  principles  underlying  the  operation  of  these 
fixtures  will  be  useful  for  us  to  have  and  may  save  much  ex- 
pense and  trouble.  We  have  already  studied  different  types 
of  faucets,  and  know  how  to  make  simple  repairs  on  them. 

Experiment.  —  To  see  how  the  siphon  works. 

Materials:     Battery   jar.     Glass   beaker.     Rubber   tube.     Glass    tube. 

Pulley  with  little  friction.     Cord  or  rope  to  go  over  the  pulley. 
Method:    (A)     Hang  a  short  heavy  cord  or  small  rope  over  the  easily 

running  pulley  with  the  two  ends  at  the  same  level.     See  figure  (a). 

Result  ?     Change  the  cord 

so  that  one  end  hangs  6 

inches  or  more  lower  than 

the  other  side.     See  figure 

(b).     Result?      (B)    Con- 
nect a  six-inch  length  of 

glass  tubing  to  one  end  of 

the  rubber  tube.     Fill  the 

entire    glass   and    rubber 

tube    with    water.     Hold 

the  finger  over  the  end  of 

the  glass  and  put  the  end 

of  the  rubber  tube  into  a 

jar  of   water.     Hold    the 

end  of  the  glass  tube  just 

below   the   level    of    the 

water  in  the  jar,  and  open 

it.     Carefully    raise     the 

tube  until  the  end  is  just 

level  with  the  water  sur- 
face in  the  jar.     See  figure  (c).     Does  water  run  out?     Does  it  run 

back?     Give  reason.     Lower  the  end  of  the  glass  tube  so  that  it  is 

several  inches  below  the  level  of  the  water  in  the  jar  to  (d)  in  figure. 

Result  ?     Explain.     What  will  happen  if  it  is  raised  above  the  level  of 

water  in  the  jar?     Try  it. 
Conclusion:  The  tube  is  used  in  this  experiment  as  a  siphon.     Explain 

how  much  of  the  action  of  the  siphon  depends  on  the  pressure  of  the 

atmosphere.     How  does  the  analogy  with  the  rope  help  to  explain  a 

part  of  the  action  of  the  siphon  ? 


150    HOW  WASTES  ARE  REMOVED   FROM  THE  HOME 

A  flush  tank.  —  If  you  will  examine  the  diagram  accom- 
panying this  paragraph  carefully,  you  will  find  that  water 
gets  into  the  tank  through  the  action  of  the  ball  float, 
which,  when  the  toilet  is  flushed,  opens  a  valve  and  allows 
a  new  supply  of  water  to  come  into  the  tank.  When  the 
water  reaches  a  certain  level  the  float  automatically  closes 
the  valve.  The  toilet  itself  is  flushed  by  pulling  a  lever 


The  bathroom  flush  tank. 

which  opens  the  valve  at  the  base  of  the  siphon.  As  the 
water  begins  to  flow  this  valve  closes,  and  the  water  in  the 
pipe  leading  to  the  toilet  acts  as  the  plunger  of  a  piston  (see 
diagram) ,  and  water  is  passed  into  the  flush  pipe  through 
the  siphon.  As  soon  as  the  water  in  the  tank  is  lowered 
to  the  point  D  the  siphon  tube  fills  with  air  and  the  action 
stops.  The  tank  then  fills  up  as  has  been  shown  pre- 
viously. 

The  study  of  your  own  home  flush  tank  makes  an  inter- 
esting experiment. 


THE  HOME   SYSTEM  OF  DRAIN  PIPES 


Experiment.  —  To  understand  how  the  flush  tank  works. 

Remove  the  cover  from  the  flush  tank.  (A)  Pull  the  lever  to  allow  the 
water  to  run  out.  Locate  the  inlet  valve.  Where  is  it?  What  con- 
trols it  ?  Make  a  diagram  to  show  clearly  how  the  water  inlet  is  con- 
trolled. (B)  Hold  the  ball-float  valve  to  prevent  more  water  entering 
the  tank.  Pull  the  lever  to  empty  the  tank.  Notice  whether  the  tank 
is  emptied  by  use  of  a  siphon  or  whether  there  is  a  rubber  ball  valve. 
If  it  has  a  ball  valve,  fill  with  water  again  and  empty.  Observe  just 
when  the  ball  closes  the  valve.  Can  you  explain  why  the  valve  stays 
open  just  so  long?  Make  one  or  more  diagrams  to  show  the  empty- 
ing mechanism.  How  would  you  make  repairs  if  the  rubber  valve 
leaked?  What  would  you  do  if  the  ball  float  were  broken  off? 

The  home  system  of  drain  pipes.  —  In  order  to  get  water 
and  wastes  out  of  the  house  it  is  necessary  to  have  a  system 
of  drain  pipes  consisting 
of  a  large  soil  pipe  from 
cellar  to  roof.  All  the 
sinks,  toilets,  and  tubs 
must  connect  with  this 
soil  pipe.  It  is  neces- 
sary, then,  to  arrange  our 
house  so  as  to  have  all 
of  the  fixtures  grouped 
about  this  drain  pipe. 
The  pipe  must  leave  the 
house  at  a  point  slightly 
lower  than  at  any  other 
place,  and  all  pipes  leav- 
ing fixtures  must  also 
run  slightly  down  hill. 
The  large  and  straight 

pipes  are  usually  iron  with  the  joints  tightly  closed 
by  means  of  cement  substances,  while  the  smaller  pipes 
are  usually  lead.  In  order  to  prevent  odors  from  de- 


An  S-trap  showing  water  seal  and  vent. 


152    HOW  WASTES   ARE   REMOVED   FROM   THE   HOME 

caying  substances  or  sewer  gas  from  getting  into  the 
house,  fixtures  known  as  traps  are  necessary.  A  study 
of  the  figure  on  page  151  shows  that  the  trap  is  an  inverted 
siphon,  and  forms  a  water  seal  which  prevents  any  gas 
from  going  by  the  water.  A  good  example  of  such  a  water 
seal  is  seen  in  the  refrigerator  trap,  where  the  water  seal 
is  used  to  prevent  warm  air  from  getting  in  to  melt  the  ice. 


Why  well  water  is  sometimes  unsafe. 

In  the  water  seal  or  traps  in  our  houses,  the  vent  (see  fig- 
ure) is  usually  necessary  to  keep  the  air  pressure  equal 
on  each  side  of  the  trap,  so  that  the  water  will  not  be  all 
sucked  out,  thus  leaving  no  protection  against  odors. 

Under  the  kitchen  sink  we  often  find  a  grease  trap.  This 
is  fitted,  as  are  all  other  traps,  with  a  cap  which  is  easily 
accessible,  and  which  can  be  unscrewed  to  remove  the 
grease  which  otherwise  might  clog  the  drain  pipes. 

Disposal  of  sewage.  —  Where  there  is  no  city  sewage 
system  the  disposal  of  sewage  is  a  most  important  ques- 


THE   SEPTIC  TANK  153 

tion.  In  homes  where  no  proper  provision  is  made,  we 
frequently  find  sewage  running  into  open  drains,  or  even 
upon  the  soil,  there  becoming  a  dangerous  menace  to 
health.  Most  country  homes  nowadays  have  a  cesspool. 
This  is  nothing  more  or  less  than  a  deep  hole  dug  in  the 
earth,  having  an  open  bottom,  uncemented  rock  or  brick 
walls  and  a  covered  top.  It  is  situated  a  few  feet  away 
from  the  house,  and  receives  all  the  sewage  which  drains 
out  gradually  through  holes  at  the  sides  and  bottom  into 
the  surrounding  soil.  If  a  great  deal  of  water  is  used,  the 
cesspool  is  too  small,  and  satisfactory  drainage  is  impos- 
sible. Moreover,  unless  great  care  is  taken,  there  is  dan- 
ger of  drainage  into  a  near-by  well.  In  clayey  soils,  cess- 
pools give  much  trouble,  as  little  drainage  takes  place,  and 
frequent  pumping  out  is  necessary.  A  cesspool  should  be 
simply  a  temporary  means  of  getting  rid  of  sewage. 

The  septic  tank.  —  By  far  the  most  modern  and  hygienic 
method  of  sewage  disposal  is  by  means  of  what  is  known 
as  the  septic  tank.  It  has  been  discovered  that?  there  are 
two  types  of  bacteria,  one  of  which  (anaerobic)  thrives 
without  air,  releasing  oxygen  from  the  substances  on  which 
it  feeds,  and  another  (aerobic)  that  must  have  air.  The 
septic  tank  is  made  with  at  least  two  compartments,  both  of 
which  are  made  of  cement  and  are  water-tight.  In  the  first 
compartment  sewage  from  the  house  flows,  and  is  there 
attacked  by  the  anaerobic  bacteria,  which  cause  the  solid 
matter  to  become  liquid.  Fats  and  other  substances  rise 
to  the  surface,  forming  an  almost  air-tight  scum,  which 
assists  the  anaerobic  bacteria  to  do  their  work  more  effec- 
tively. As  the  sewage  is  decomposed  it  passes  into  the 
second  tank  in  an  almost  colorless  and  odorless  condition. 
When  this  tank  fills  its  contents  are  siphoned  off  into 


154    HOW  WASTES   ARK    KKMOVEI)    I  ROM   THE  HOME 


drains  under  the  surface  of  the  ground.     This  sewage  is 
now  quite   harmless,   as  all  organic  contents  have  been 


A  septic  tank. 

decomposed  or  oxidized  by  the  bacteria,  so  that  no  harm 
can  come  from  it.  Several  different  types  of  septic  tanks 
are  now  on  the  market,  and  they  are  infinitely  better  than 
the  old  type  of  cesspool.  The  liquid  leaving  the  septic 
tank  contains  much  valuable  fertilizing  material,  and  is 
generally  used  on  the  home  garden. 

Sanitary  garbage  pails  and  their  care. — We  have  already 
learned  that  flies  feed  and  lay  their  eggs  in  garbage.  The 
garbage  pail  should  be  of  metal  so  that  it  can  easily  be  scalded 
and  should  have  a  tight-fitting  cover.  During  the  summer 
it  should  be  emptied  every  day  or  two,  as  otherwise  the 
bacteria  of  decay  will  cause  the  refuse  contained  in  it  to 
smell  badly.  If  the  garbage  is  not  taken  up  by  a  collector 
it  ought  to  be  either  burned  or  buried  so  deep  that  the 
flies  cannot  get  at  it.  If  we  live  on  a  farm  all  the  fresh 
garbage  should  be  fed  to  the ,  pigs  or  chickens  daily.  The 
pail  should  be  kept  covered  in  an  inconspicuous  place  and, 
as  every  good  housewife  knows,  should  be  sterilized  with 


USE  OF  THE  SCORE   CARD 


155 


boiling  water  and  washing  soda  at  least  twice  a  week 
during  the  hot  weather.  If  these  rules  are  observed  we 
shall  have  no  trouble  from  the  garbage  pail  during  hot 
weather. 

Use  of  the  score  card.  —  Here  again  the  city  boy  and 
g'rl  have  an  advantage  over  his  or  her  country  cousin. 
This  means  more  care  and  an  honest  attempt  to  improve 
conditions  on  the  part  of  those  whose  environment  is  not 
so  favorable.  And  we  must  also  remember  that  city  condi- 
tions are  sometimes  much  worse  than  country  conditions 
because  of  lack  of  repair  of  fixtures  or  carelessness  on  the 
part  of  users.  So  both  city  and  country  dwellers  may  have 
to  make  low  scores.  Remember  that,  after  all,  improve- 
ment is  the  big  thing. 

SCORE  CARD.    REMOVAL  OF  WASTES    FROM  MY  HOME 


MY  SCORE 

EXCELLENT 

FAIR 

VERY  POOR 

TOTAL 

SYSTEM 
OF 

Exposed    plumbing 
throughout  (2) 

Exposed    plumbing 
in  bathroom  and 

No  exposed  plumb- 
ing (o) 

PLUMB- 

sink (i) 

ING 

All  parts  of  system 
having  traps  (toi- 

Traps at  toilet  and 
sink  (i) 

No  traps  (o) 

let,    bowl,   bath- 

tub,  sink,    tubs) 

(2)  f 

All    pipes    laid    at 

Not    all    pipes    at 

slight  grade  (2) 
Ventilation      ducts 

Ventilation      ducts 

grade  (o) 
No  ventilation 

provided  (2) 

not  always   pro- 

ducts (o) 

vided  (i) 

Trap  at  house  exit 

No   trap  at   house 

(2) 

exit  (o) 

TOILET 
AND 

All     porcelain     or 
enameled         fix- 

Porcelain or  enam- 
eled         fixtures, 

No     porcelain     or 
enameled         fix- 

BATH- 

tures,    including 

wooden  seat  (2) 

tures  (o) 

ROOM 

toilet  seat  (3) 

•  •  .  • 

FIXTURES 

Bathtub,  foot  tub, 

Bathtub,  no  show- 

No bathtub  (o) 

and  shower  (2) 

er  or  foot  tub  (i) 

.... 

More      than      one 

One  bathroom  (2) 

No  bathroom  (o) 

bathroom  (2) 

Lavatory  and  toilet 

Lavatory    only    on 

No  lavatory  (o) 

on    ground    floor 

ground  floor  (i) 

(3) 

.... 

156    HOW  WASTES   ARE   REMOVED   FROM   THE   HOME 


SCORE    CARD. 


REMOVAL    OF   WASTES   FROM    MY   HOME 

—  Continued 


MY  S 

CORE 

EXCELLENT 

FAIR 

VERY  POOR 

TOTAL 

KNOWL- 

Sufficient      knowl- 

Knowledge    which 

No    knowledge    of 

EDGE 

edge  of  system  to 

will  give  sufficient 

system.         Must 

OF 

information      t  o 

call  plumber  and 

SYSTEM 

call    plumber    to 

let  him  find  out 

(a)     Clean     out 

(a)     Clean     out 

the  trouble  (o) 

trap  (3) 
(b)     Clean     out 

trap  d) 
(b)     Clean     out 

.... 

grease  trap  (3) 
(c)    Repair   flush 

grease    trap    (i) 
(c)      Fix      flush 

tank  float  (4) 

tank  float  (i) 



SEWAGE 

Sewage   connection 

Cesspool  (5) 

Sewage    flows    un- 

CONNEC- 

with town  or  city 

treated  into  open 

TION 

system  (10) 

drains  (o) 

Septic   tank,  prop- 

Septic   tank    occa- 

erly working  (10) 

sionally       giving 

trouble  (5) 

(Score  only  one  of 

Outdoor    privies   if 
screened  and  dis- 

Outdoor privies  not 
screened  or  disin- 

above.) 

infectant    used 

fected  (o) 

every  day  (4) 

CARE  OF 

Garbage 

Garbage 

No  garbage  collec- 

GARBAGE 

(a)  Collected  by 

(a)  Collected  by 

tion  (o) 

AND 
GARBAGE 

city  daily 
(b)  burned  daily 

city  once  a  week 
(b)  burned  once  a 

Garbage  burned  ev- 
ery two  weeks  (o) 

PAIL 

week 

Garbage    scattered 

(c)  buried  at  least 

(c)     buried     six 

over    garden    in 

2  ft.  under  sur- 

inches  under 

summer  (o) 

face  daily 

surface 

(d)    fed    to    pigs 

(d)  fed  to  pigs  or 

and  chickens  one 

chickens   once   a 

day  after  collec- 

week (any  meth- 

tion   (any  meth- 

od) (ij) 

od)  (3) 

Metal     pail     with 

Metal    pail,    loose 

Wooden     pail,     no 

tight  cover  (2) 

cover  (i) 

cover  (o) 

Pail  emptied  daily 
in  summer  (2) 

Pail  emptied  week- 
ly d) 

Pail    not    emptied 
of  tener  than  once 

every  two  weeks 

Pail  sterilized  twice 

Pail    sterilized 

(o) 
Pail   not    sterilized 

a  week  in  sum- 

weekly (i) 

more  often  than 

mer  (2) 

once    every    two 

weeks  (o) 

Pail  kept  in  incon- 

Pail with  some  odor 

Bad  odor  from  gar- 

spicuous place  — 

(i) 

bage  (o) 

no  odors  (i) 

GRAND 

TOTAL 

REFERENCE  BOOKS  157 

REFERENCE  BOOKS 

Broadhurst,  Home  and  Community  Hygiene,  Chapter  VII  (Teacher's  use).    J.  B. 

Lippincott  Company. 

Butler,  Household  Physics,  pages  356-364.     Whitcomb  and  Barrows. 
Caldwell  and  Eikenberry,  General  Science,  Chapter  XIV.     Ginn  and  Company. 
Chapin,  Sources  and  Modes  of  Infection   (Advanced    and    teacher's  use).     John 

Wiley  and  Sons. 

Hunter,  A  Civic  Biology,  Chapters  XXII,  XXIV.     American  Book   Company. 
Lynde,  Physics  of  the  Household,  Chapter  VII.     The  Macmillan  Company. 
Winslow,  Healthy  Living,  Chapter  XII.     Charles  E.  Merrill  Company. 


CHAPTER   X 


GERM   DANGERS   AND   HEALTH   HABITS 

Problems.  —  i.    To  understand  the  relation  of  bacteria 
to  disease. 

2.  To  discover  the  defenses  of  our  body  against  germs. 

3.  To  see  how  habits  control  our  health. 

4.  To  learn  good  health  habits. 

Experiments. —  i.  To 
show  how  infection  takes 
place. 

2.  To  make  a  hygienic 
drinking  cup. 

Project  I.  —  To  COM- 
PARE MY  DAILY  USE  OF 
TIME  WITH  AN  IDEAL 
PLAN. 

i.  Make  two  circles 
with  diameters  of  3! 
inches.  Just  inside  the 
circles  put  in  two  series 
of  figures,  i  to  12, 
equally  spaced  to  rep- 
resent the  twenty-four 
hours  of  the  day.  (See 
diagram.) 

2.   In  one  of  these  mark  out  the  spaces  representing  time  given  to 
various  things  suggested  as  ideal. 

158 


Tlicliviglvt 


This  is  one  pupil's  daily  program  for  five  days  a 
week. 


WHAT  BACTERIA  LOOK  LIKE 


3.  Keep  a  record  of  your  own  habits  in  these  matters  for  one  week. 
Average  these,  and  on  the  basis  of  the  averages  fill  out  the  second 
circle  to  represent  your  own  daily  schedule. 

Project  II.  —  To  FORM  CORRECT  HEALTH  HABITS. 

Join  the  "  Health  Crusaders."  Perform  their  assigned  tasks 
regularly  and  make  proper  records.  Keep  a  monthly  record  as  sug- 
gested by  the  following  table. 

PHYSICAL  EXAMINATION 


MONTHLY  RECORD 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

i.   Weight      .    ,. 

2.   Height      .     . 

3.   Chest  measure 

(i)   Inflated     . 

(a)   Deflated    . 

(3)    Chest     ex- 

pansion = 

4.   Lung    capac- 

ity     .... 

5.   Time       can 

hold  breath 

6.   Eye  test    .     . 

7.   Hearing    .     . 

8.    Grip  test  .     . 

9.   Lifting 

strength  .     .     . 

10.  Age      .     .     . 

Where  germs  live  and  how  they  grow.  —  Some  one  has 
said  that  bacteria  exist  "  anywhere  but  not  everywhere." 
They  swarm  in  soils,  in  impure  water,  in  stale  milk,  in  the 
dead  bodies  of  plants  and  animals,  and  to  a  certain  extent 
in  living  bodies  as  well.  They  cause  decay,  and  so  far  as  we 
know,  all  "  catching  "  diseases.  We  could  tell  many  other 
things  they  do,  and  we  have  already  seen  some  of  them. 

What  bacteria  look  like.  —  It  is  easy  to  see  the  effect 
of  bacteria  on  milk  when  it  sours  and  on  food  when  it 
decays,  or  to  observe  colonies  of  them  growing  in  a  Petri 


160          GERM  DANGERS  AND   HEALTH  HABITS 


dish,  yet  each  bacterium  is  so  small  that  it  is  visible  only 
under  a  very  high  power  microscope.  Bacteria  are  single- 
celled  plants,  unable  to  make  their  own  food,  and  con- 


Types  of  bacteria,     i.  Rods.     2.  Spheres.     3.  Spirals. 

sequently  do  much  harm  by  living  at  the  expense  of 
other  things,  as  upon  dead  organic  material.  Some  one  has 
said  that  in  order  to  recall  their  forms  one  must  think  of 
a  billiard  cue,  a  billiard  ball,  and  a  corkscrew.  A  glance 
at  the  illustration  will  show  how  true  this  statement  is. 
They  are  rodlike  (called  bacillus),  ball-like  (called  coccus), 
or  spiral  (named  spirillum)  in  form.  Many  kinds  can 
move  with  great  speed  through  the  water  by  means  of 
tiny  threadlike  structures  which  vibrate  rapidly.  They 
never  thrive  except  in  moisture,  although 
some  of  them  may  be  dried  and  float 
around  in  the  air  some  time  without  dy- 
ing, becoming  active  again  when  moist. 
Many  forms  endure  an  unfavorable  en- 
vironment of  heat  and  cold  as  well  as 
dryness  by  forming  a  thick  resistant 
coat  about  their  body.  In  this  condi- 
tion they  are  called  spores. 

How   germs   cause   disease.  —  It  has  been   estimated 
that  over  fifty  per  cent  of  the  people  who  die  each  year  are 


Bacteria  forming  spores. 


METHODS  OF  INFECTION  161 

killed  by  bacteria.  A  very  large  portion  of  the  infectious 
diseases  might  be  prevented  if  people  knew  more  about 
the  ways  by  which  germs  enter  the  body  and  were  more 
careful  to  keep  them  out.  It  may  help  us  to  see  how 
germs  get  into  the  body  if  we  study  the  way  in  which  an 
apple  is  protected  against  infection  and  by  what  means  it 
is  infected. 

Experiment.  —  To  show  how  infection  takes  place. 

Materials:  A  sound  apple.     A  decaying  apple.     Toothpicks. 

Method:  (a)  Make  a  small  irregular  hole  through  the  skin  of  the  sound 
apple.  Fill  this  with  decaying  pulp  from  the  other  apple,  (b)  Stick 
a  toothpick  into  the  rot  of  the  decaying  apple  and  then  stick  it  into 
the  sound  apple,  leaving  it  there,  (c)  Sterilize  a  toothpick  by  pass- 
ing one  end  of  it  through  a  flame  several  times  without  allowing  it  to 
take  fire.  Stick  this  end  of  the  toothpick  into  the  apple  and  leave  it. 
(d)  In  a  four-inch  area  on  the  unbroken  and  unbruised  skin  of  the 
sound  apple  lay  a  little  of  the  decaying  apple  pulp.  Set  the  apple 
away  in  a  dark,  warm  place. 

Observation  and  Conclusion:  Examine  the  apple  daily  until  changes  have 
occurred  in  one  or  more  of  the  places.  Where  does  infection  occur? 
Explain  what  natural  defense  against  infection  the  apple  has,  but  how 
conditions  may  arise  in  which  decay  results. 

Methods  of  infection.  —  When  we  take  germ  diseases 
the  germs  enter  our  bodies  by  means  of  the  nose,  mouth, 
through  body  openings,  or  through  a  break  in  the  skin. 
They  may  be  carried  by  means,  of  food,  water,  or  even 
through  the  air,  and  the  germs  usually  are  taken  directly 
from  a  person  who  has  the  disease.  The  most  common 
method  of  spreading  disease  is  by  sneezing  or  coughing,  or 
even  breathing  and  talking  close  to  the  face  of  some  one 
else.  If  you  have  ever  watched  a  person  talk  when  in  the 
sunshine,  you  may  have  observed  a  constant  spray  of  tiny 
droplets  which  are  forced  out  from  the  mouth.  These 
droplets  are  sprayed  from  two  to  three  feet  from  the 

H.-WHIT.    CIV.    SCI.    IN   THE   HOME  —  II 


162 


GERM   DANGERS   AND   HEALTH   HABITS 


mouth  of  the  person.  Most  children's  "  catching  "  diseases 
begin  with  sore  throat,  sneezing,  and  coughing.  Measles, 
whooping  cough,  scarlet  fever,  tonsillitis,  influenza,  and 
diphtheria  all  begin  in  this  way,  hence  it  is  very  easy  for 
any  one  unthink- 
ingly to  spray  out 
the  germs  when 
coughing,  sneezing, 
or  even  talking,  and 


10J 


t. 


A  common  method  of  spreading  germs.     (After 
Winslow.) 


thus  to  infect  some 
one  else.  A  good 
health  habit  to  form 
very  early  in  life  is 
that  of  the  proper 
use  of  the  handkerchief.  Never  cough  or  sneeze  into 
the  open  air,  but  into  a  handkerchief.  Keep  the  nose 
well  blown  to  prevent  an  unpleasant  appearance  as  well 
as  possible  spread  of  colds.  A  "  common  cold "  soon 
becomes  everybody's  cold  in  a  schoolroom  in  which  the 
children  do  not  have  the  proper  health  habits.  A  good 
rule  to  observe  with  reference  to  colds  is  this:  remain 
quietly  at  home  resting  in  bed,  for  thus  one  will  not  only 
prevent  others  from  "  catching  "  it,  but  by  rest  and  proper 
food  it  will  soon  be  cured. 

Disinfectants  and  how  to  use  them.  —  Sometimes  it 
becomes  necessary  in  our  homes  to  destroy  the  bacteria 
which  cause  disease.  This  is  done  by  the  use  of  disinfect- 
ants. Many  different  substances  which  have  a  deadly 
action  on  bacteria  can  be  obtained  at  the  drug  store. 
Inasmuch  as  these  substances,  such  as  carbolic  acid,  lysol, 
bichloride  of  mercury,  and  formaldehyde,  are  deadly  poisons, 
we  must  exercise  the  greatest  care  in  their  use.  For  disin- 


AIR  AND   HEALTH  163 

fecting  wounds  or  cuts  iodine  is  much  used ;  while  for  use 
on  hands,  a  weak  (i  to  25  parts  water)  solution  of  carbolic 
acid  followed  by  scrubbing  with  green  soap  is  safe  and  sure. 

Our  body  defenses  against  disease.  —  Germ  diseases 
are  usually  caused  by  poisonous  toxins.  These  are  waste 
materials  given  off  by  bacteria  which  act  upon  the  individ- 
ual like  snake  venom.  Some  people  are  very  much  more 
resistant  to  these  toxins  than  others,  and  therefore  are  less 
likely  to  take  "  catching  diseases."  This  resistance  to  or 
defense  against  disease,  when  powerful  enough  to  kill  the 
germs  or  offset  the  harm  from  toxins,  produces  an  immu- 
nity. Immunity  may  be  natural,  or  it  may  be  acquired  in 
the  case  of  some  diseases.  This,  for  example,  is  done  in 
the  case  of  diphtheria  by  means  of  antitoxin  treatment, 
and  in  the  case  of  small  pox  and  typhoid,  by  means  of 
vaccination.  The  theories  underlying  immunity  will  be 
discussed  more  fully  in  the  next  book.  Natural  immunity, 
however,  may  be  increased  by  keeping  the  body  in  just 
as  good  condition  as  possible.  Proper  habits  of  health  as 
suggested  in  the  following  paragraphs  will  assist  greatly 
in  maintaining  one's  health. 

Air  and  health.  —  We  have  already  referred  to  the  need 
of  oxygen.  It  is  generally  agreed  at  the  present  time  that 
we  must  have  as  much  fresh  air  as  possible,  that  our  rooms 
must  be  well  ventilated,  that  porous  clothes  must  be  worn 
so  that  the  body  can  have  a  constant  air  bath,  for  the  skin 
under  the  clothes  needs  air  as  well  as  the  parts  exposed. 
We  have  come  to  depend  upon  outdoor  play  and  outdoor 
sleeping  as  means  of  good  health.  We  should  always 
practice  good  posture  and  acquire  good  breathing  habits. 
An  excellent  habit  is  that  of  morning  exercise  with  the  win- 
dows thrown  open.  Remember  that  the  lungs  need  exercise 


164          GERM   DANGERS   AND   HEALTH  HABITS 


Simple  foods  are  nourishing. 


Indigestible  foods. 


Bulky  foods.     (Eastman  Kodak  Co.) 


CARE  OF  THE  TEETH 


165 


and  air,  and  that  only  by  deep  breathing  which  expels 
much  of  the  stagnant  air  which  accumulates  in  the  lungs 
can  we  make  them  resistant  against  disease  germs. 

Food  and  health.  —  Boys  and  girls  should  eat  enough, 
but  not  too  much.  They  should  not  eat  when  very  tired, 
and  should  eat  only  a  light  meal  at  night.  Hard  and  bulky 
foods  should  be  included  in  the  menu,  since  they  tend  to 
prevent  constipation.  Raw  foods  containing  vitamines 
should  always  be  a  part  of  the  diet,  especially  uncooked 
milk,  fresh  fruits,  and  fresh  vegetables,  but  all  raw 
foods  should  be  carefully  washed  because  of  danger  from 
germs. 

Care  of  the  teeth.  —  Thorough  chewing  of  the  food  is 
necessary  for  good  health.  Many  of  us  bolt  our  food,  and 
as  a  result  suffer  from  indigestion.  The  teeth  are  important 
factors  in  the  habit  of  proper  chewing.  We  can  form  no 
better  habit  than  that  of  properly  brushing  them.  The 
teeth  should  be  brushed  at  least  twice  a  day,  and  not  only 
the  teeth  but  also  the  gums  around  them.  Brushing  up 


L" 


Results  of  neglect  and  care  of  teeth. 

and  down  rather  than  across  the  teeth  is  of  much  more 
value,  because  it  dislodges  the  food  particles  held  between 
the  teeth,  and  thus  prevents  their  decay.  The  teeth  should 
be  examined  by  a  dentist  at  least  twice  a  year,  for  this  will 
save  much  pain  and  possible  loss  later  on.  Decay  of  the 


i66          GERM  DANGERS  AND  HEALTH  HABITS 

teeth  comes  as  a  result  of  bacteria  lodging  in  the  same 
crevices  with  food.  They  pour  out  an  acid  waste  sub- 
stance which  attacks  the  hard  enamel  of  the  teeth,  breaking 
it  down  and  thus  allowing  germs  gradually  to  attack  the 
living  portion  of  the  teeth  underneath.  Upon  our  teeth 
depends  much  of  our  health  later  on  in  life,  so  let  us  form 
habits  of  proper  care  of  them  while  we  are  young. 

Body  poisons  and  good  health.  —  One  of  the  best  habits 
to  get  early  in  life  is  that  of  regularity  of  bowel  movement 
for  thus  we  may  be  spared  the  evils  which  come  through 
constipation.  As  we  have  studied  before,  the  lower  part  of 
the  food  tube,  if  not  emptied  regularly,  becomes  rilled  with 
decaying  material,  for  this  part  of  the  food  tube  is  always 

alive  with  millions  of 
bacteria,  which  cause 
decay.  As  this  decay 
takes  place,  the  soluble 
poisons  set  free  are 
easily  passed  through 

the    Wal1    °f     the 


Drink  si*  glasses  of  water  a  day. 

and  get  into  the  blood, 

causing  headache  and  a  feeling  of  discomfort  which  often 
attends  constipation.  Excellent  suggestions  which  will  help 
us  to  fight  this  evil  are  the  following.  Drink  a  glass  of  water 
when  you  get  up  in  the  morning,  and  at  least  one  glass  before 
each  meal.  Take  plenty  of  raw  or  cooked  fruits  except 
bananas,  blackberries,  and  raspberries.  Green  vegetables, 
whole  wheat  bread,  bran  muffins,  fats,-  and  oils  are  helpful 
in  keeping  the  bowels  regular.  Avoidance  of  tea  and  coffee, 
and  proper  hours  of  sleep,  all  help  in  fighting  this  evil. 

Get  the  habit  of  using  your  own  cup  when  you  drink. 
Every  one  should  know  how  to  make  his  own  drinking  cup. 


EXERCISE  AND   HEALTH 


167 


Follow  the  directions  given  in  the  accompanying  diagram, 
and  see  if  you  can  make  yours. 


A 

square 
piece 

& 
paper 


Fold 
A  on  ts  B 


along  the  line 
D  —  C. 


F  en  the  line  A C 


the  line 


F.   and 

scnitarcj 
CUP 


(After  Tolman.) 
Experiment.  —  To  make  a  hygienic  drinking  cup. 

Materials:   A  sheet  of  strong  clean  paper  six  to  eight  inches  square. 
Method:   Fold  as  suggested  in  the  accompanying  diagram. 

Exercise  and  health.  —  Most  boys  and  girls  may  exer- 
cise enough,  but  not  properly.  Especially  in  the  case  of 
girls,  proper  posture,  or  poise  of  the  body,  in  walking,  sitting, 


i68 


GERM   DANGERS   AND   HEALTH   HABITS 


and  standing,  is  necessary.  The  bad  habit  of  sprawling  over 
the  desk  or  table  when  at  work  makes  for  round-shouldered, 
small-chested  men  and  women.  Learn  to  set  the  shoulders 
square  and  back,  keep  the  chest  high  and  out,  and  both  the 
stomach  and  chin  in.  Military  training,  such  as  our  young 
men  have  had  in  the  great  World  War,  has  done  much  to 
increase  their  bodily  resistance  to  disease,  and  to  make 
strong  men  of  weaklings. 


HOME  DUTIES   OF  CHILDREN 


MY  OWN  RECORD 

TIME.  MIN- 
UTES PER 
DAY 

SCORE 

i.   Sweeping  and  dusting  generalrooms    
2.   Full  charge  of  own  chamber  
3.   Making  beds    
4.   Helping  cook   ...          

5     Ironing 

8.   Taking  care  of  furnace       
9.   Taking  care  of  hens  and  chickens    
10    Tending  baby 

11.   Taking  care  of  a  pet  :  dog,  cat,  bird,  fish,  or  rabbit 
12    Taking  care  of  garden  and  lawn      

14    Setting  tables                                

15    Washing  dishes  running  errands 

16.   Other  work       

TOTAL                                                                           .... 

Copy  this  form  of  record  in  notebook. 

Register  average  time  per  day  given  to  work  here  listed. 

A  total  of  ip  points  for  every  15  minutes  devoted  to  any  duty  daily. 

Boys  and  girls  will  score  extra  work  not  mentioned  here  under  16.  No  score 
allowed  over  100.  Two  and  one  half  hours  daily  home  work  outside  of  school 
work  entitles  you  to  a  perfect  score. 

Home  duties.  —  Every  boy  and  girl  ought  to  have  a 
part  in  the  duties  as  well  as  the  pleasures  of  the  home. 
It  is  unfair  to  mother  and  father  to  have  them  assume  all 
the  care  of  the  house,  and  it  ought  to  be  part  of  your 


HABITS  OF  CLEANLINESS  169 

training  to  have  a  practical  knowledge  of  how  the  house 
is  made  to  run  smoothly.  Besides  this,  there  is  a  certain 
amount  of  healthful  exercise  in  weeding  the  garden  or 
cleaning  the  walk  or  bringing  up  the  coal  or  running  a 
sewing  machine  or  a  churn.  The  score  card  on  page  168 
will  give  you  some  idea  of  how  well  you  are  living  up  to 
your  part  of  the  home  duties. 

Rest  and  health.  —  Our  days  should  be  made  up  of  work 
and  play,  rest  and  sleep.  It  is  just  as  bad  to  over-exer- 
cise-, as  it  is  to  under-exercise.  One  should  remember 
that  all  machines  need  rest,  and  the  human  machine  is 
no  exception  to  the  rule.  At  least  eight 
hours  of  sleep  should  be  had  by  every 
boy  and  girl  of  high  school  age,  and 
nine  or  ten  hours  of  sleep  by  younger 
children.  Fewer  movies  and  more  quiet 
reading  at  home  would  be  good  for  every 
boy  and  girl.  Moderation  in  all  things  is 
a  good  rule.  Overstrain  of  any  kind 
brings  on  fatigue,  and  in  the  end  shows 


. .-,  Time  for  sleep. 

that  we  cannot  strain  an  organ  without 
paying  for  it.  If  we  overstrain  the  eyes,  for  example,  we 
pay  for  it  by  wearing  glasses  later.  If  we  overstrain  in 
athletics,  we  may  have  to  give  up  athletics  altogether. 
Over-fatigue  by  keeping  too  late  hours  will  surely  call  us  to 
account  later  in  life.  Let  us  learn  while  young  the  value 
of  complete  relaxation,  and  let  us,  while  we  are  growing, 
get  the  habit  of  going  to  bed  at  the  proper  hour. 

Habits  of  cleanliness.  —  "  Cleanliness  is  next  to  god- 
liness "  is  an  old  saying,  and  a  good  one.  Habits  of  clean- 
liness at  meals  are  particularly  necessary.  One  should 
always  wash  the  hands  after  going  to  the  toilet.  Bathing 


170 


GERM   DANGERS   AND   HEALTH   HABITS 


the  entire  body  at  least  once  a  week  should  be  a  habit,  and 
if  the  feet  or  body  become  covered  with  perspiration  in 
warm  weather,  one  should  bathe  more  frequently. 


Always  wash  the  hands  before  eating.     (Eastman  Kodak  Co.) 

Not  only  should  we  get  the  habit  of  cleanliness  of  body, 
but  we  should  also  early  in  life  strive  for  habits  of  cleanli- 
ness of  mind.  We  should  learn  to  keep  watch  upon  our 
thoughts  as  well  as  upon  our  bodies,  for  purity  of  mind  as 
well  as  purity  of  body  will  have  an  effect  on  health  as  well 
as  an  influence  over  others. 

The  use  and  abuse  of  drugs.  —  One  degrading  habit  to 
which  Americans  are  addicted  is  the  use  of  patent  medicines 
and  drugs. .  American  newspapers  annually  receive  fully 
$40,000,000  for  advertising  patent  medicines;  how  much 
more  must  the  manufacturers  of  these  medicines  receive  ? 
It  should  be  a  rule  never  to  use  a  patent  medicine  unless 
it  is  prescribed  by  our  physician.  The  body  is  a  delicate 


THE  USE  AND  ABUSE  OF  DRUGS  171 

machine,  and  easily  put  out  of  running  condition.  If  it  is 
out  of  order  a  physician  should  be  consulted,  and  one 
should  not  try  to  "  doctor  "  himself.  Boys  and  girls 
should  not  drink  tea  and  coffee.  Cocoa  and  milk  are  bet- 
ter beverages,  as  they  are  food  substances;  while  neither 
tea  nor  coffee  have  any  food  value,  and  are  dangerous  for 
young  people  because  they  are  apt  to  make  them  form  the 
habit  of  drinking  tea  and  coffee  to  excess.  It  goes  with- 
out saying  that  alcohol  in  any  form  should  not  be  used. 
Tobacco  has  been  proved  to  have  a  bad  effect  upon  grow- 
ing boys.  Dr.  Seaver  of  the  physical  training  department 
of  Yale  College  some  years  ago  made  a  careful  comparison 
of  the  growth  of  smokers  and  non-smokers  during  their 
four  years  in  college.  He  found  that  students  who  did  not 


Alcoholic  drink,  tea,  coffee,  and  tobacco  are  especially  harmful  during  the  years  of 

bodily  growth. 

use  tobacco  gained  ten  per  cent  more  in  weight,  twenty- 
four  per  cent  more  in  height,  twenty-seven  per  cent  more 
in  chest  expansion,  and  seventy-seven  per  cent  more  in  lung 
capacity  than  did  the  smokers.  The  tobacco  heart  of 


172          GERM  DANGERS  AND  HEALTH  HABITS 

smokers  is  well  known  to  the  athlete,  and  no  boy  who  is  in 
training  can  have  any  doubt  that  the  use  of  tobacco  has  a 
definite  effect  on  his  "  wind  "  when  he  trains  for  some 
athletic  contest. 

Fifteen  health  rules.  —  One  of  the  most  interesting  and 
helpful  books  written  in  late  years  is  the  manual,  How 
to  Live,  by  Professor  Irving  Fisher  and  Dr.  E.  L.  Fisk. 
They  summarize  the  health  habits  given  in  this  chapter 
in  the  following  fifteen  rules : 

I.  AIR: 

1.  Ventilate  every  room  you  occupy. 

2.  Wear  light,  loose,  and  porous  clothes. 

3.  Seek  out-of-door  occupations  and  recreations. 

4.  Sleep  out  of  doors,  if  you  can. 

5.  Breathe  deeply. 

II.   FOOD: 

6.  Avoid  overeating. 

7.  Eat  sparingly  of  meats  and  eggs. 

8.  Eat  some  hard,  some  bulky,  some  raw  foods. 

9.  Eat  slowly. 

III.  POISONS: 

10.  Move  the  bowels  regularly  and  frequently. 

11.  Stand,  sit, "and .walk  erect. 

12.  Do  not  allow  poisons  and  infections  to  enter  the  body. 

13.  Keep  the  teeth,  gums,  and  tongue  clean. 

IV.  ACTIVITY: 

14.  Work,  play,  rest,  and  sleep  in  moderation. 

15.  Keep  happy. 

Welfare  pamphlets.  —  Much  help  in  forming  good  health 
may  be  obtained  from  the  welfare  pamphlets  such  as  those 
issued  by  the  Metropolitan  Life  Insurance  Company  and 
the  International  Harvester  Company.  Several  of  the  il- 
lustrations in  this  chapter  were  taken  from  "Good  Health 


HOW  TO  SCORE  MY  HEALTH  HABITS 


173 


and  How  to  Keep  It,"  issued  by   the  Eastman  Kodak 
Company  for  the  benefit  of  its  employees. 

How  to  score  my  health  habits.  —  Everyday  life  is 
nothing  but  repetition  of  things  over  and  over  again. 
And  that  means  our  everyday  life  becomes  habitual.  One 
great  thinker  and  teacher  has  said  that  we  are  "  bun- 
dles of  habits."  Certainly  our  daily  routine  ought  to  be 
largely  a  matter  of  habit  and  of  good  habits.  Therefore 
we  should  take  no  score  whatever  unless  each  point  men- 
tioned has  become  a  matter  of  habit.  There  ought  to  be 
a  good  many  points  that  you  can  add  to  this  score  card, 
some  of  which  may  be  of  more  importance  than  the  ones  on 
the  card.  Be  sure  to  add  these  and  bring  them  to  class 
for  discussion.  Perhaps  by  all  working  together  you  can 
make  an  ideal  card,  much  better  than  the  one  which 
follows. 

SCORE  CARD.    PERSONAL  HEALTH  HABITS 


PERFECT 
SCORE 


MY  SCORE 


Regular  daily  routine 5 

Setting-up  drill  and  deep  breathing 5 

Cool  rub  or  shower 5 

Teeth  brushed  morning  and. night     f-  ,". .  .     t     .     .     .  5 

Slow  eating  at  meals 5 

Food  chewed  well   ...;,.•• 5 

No  overeating    ....  •.  •  "."  .    .   .. '  ;    .     .     .     .  5 

Cheerfulness  at  meals      •..-•..... 5 

Regular  toilet  habits 5 

Wash  hands  often,  always  after  toilet 5 

Clean  shoes  and  clean  linen 5 

Loose,  comfortable  clothing 5 

Feet  warm  and  dry 5 

Regular  play  hours 5 

Exercise  in  open  air  two  hours  a  day 5 

Regular  work  and  study  hours  (at  least  two  hours) .     .  5 

Proper  lighting  for  study 5 

Bed  before  10  P.M 5 

Sleep  in  open  air  or  with  windows  open  top  and  bottom  5 

No  coffee,  tea,  or  cigarettes 5 

TOTAL 100 


174         GERM  DANGERS  AND  HEALTH  HABITS 
SCORE  CARD.    PROTECTION  AGAINST  DISEASE 


PERFECT 
SCORE 

MY  SCORE 

Vaccinated  for  smallpox  
Teeth  examined  twice  a  year  
All  cavities  filled 

5 
5 

Eyes  examined  once  a  year       
Glasses  used  when  necessary     
Keep  more  than  five  feet   distant  from    those  who 
cough  or  sneeze 

5 
5 

Take  care  to  use  handkerchief  if  you  cough  or  sneeze  . 
Stay  in  the  house  if  you  have  a  cold 

5 

All  clothing  clean  and  sterile  at  all  times  
Wounds  properly  disinfected  

5 
5 

i 

TOTAL 

rn 

! 

J? 

1 

REFERENCE   BOOKS 

Adams,  The  Great  American  Fraud.     American  Medical  Association. 

Broadhurst,  Home  and  Community  Hygiene,  Chapter  X  (Teacher's  use).     J.  B. 
Lippincott  Company. 

Brownell,  General  Science,  Chapter  III.     Blakiston's  Son  and  Company. 

Chapin,  Sources  and  Modes  of  Infection  (Teacher's  use).     John  Wiley  and  Sons. 

Clark,  An  Introduction  to  Science,  Chapter  XX.     The  American  Book  Company. 

Conn,  Bacteria,  Yeasts  and  Molds  of  the  Home.     Ginn  and  Company. 

Conn,  Story  of  Germ  Life.     D.  Appleton  and  Company. 

Dakin  and  Dunham,  Handbook  of  A ntiseptics  (Advanced).     The  Macmillan  Com- 
pany. 

Dorset,  Some  Common  Disinfectants.     Farmers'  Bulletin  926. 

Fisher  and  Fisk,  How  to  Live.     Funk  and  Wagnalls. 

Harmfulness  of  Headache  Mixtures.     Farmers'  Bulletin  No.  377. 
Habit-Forming  Agents.     Farmers'  Bulletin  No.  393. 

Hill,  The  New  Public  Health  (Teacher's  use).     The  Macmillan  Company. 

Hunter,  A  Civic  Biology,  Chapters  XI,  XXIV.     American  Book  Company. 

Hunter,    Laboratory   Problems   in   Civic   Biology,    Chapter   XI.     American   Book 
Company. 

Jewett,  Good  Health.     Ginn  and  Company. 

Lee,  Health  and  Disease  (For  teachers).     Little,  Brown,  and  Co. 

Prudden,  Dust  and  its  Dangers.     G.  P.  Putnam's  Sons. 

Ritchie,  Primer  of  Sanitation,  Chapters  XXXI,  XXXII.     World  Book  Company. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  IV.     Houghton 
Mifflin  Company. 

Winslow,  Healthy  Living.     Charles  E.  Merrill  Company. 

Zinsser,  Infection  and  Immunity  (For  teachers).     The  Macmillan  Company. 


PART    III.     HEAT   IN    THE    HOME 

CHAPTER  XI 
FUELS   AND   THEIR   USES 

Problems.  —  i .    To  learn  about  fuels  and  their   relative 
values. 

2 .  To  find  out  what  burns  in  fuels. 

3.  To  learn  the  difference  between  "  heat  "   and  "  tem- 
perature" 

4.  What  is  the  kindling  temperature? 

5.  How  is  heat  transferred? 

Experiments. 

1.  To  find  out  if  all  substances  take  fire  at  the  same  temperature. 

2.  To  see  if  heat  will  travel  along  a  metal  rod. 

Project  I.  —  To  MAKE  A  HOUSE  THERMOMETER. 
i     Decide  what  materials  are  needed,  and  whether  you  will  make 
an  alcohol  or  a  mercury  thermometer. 

2.  Practice  glass  working  so  that  you  can  blow  bulbs  in  common 
glass  tubing  before  trying  thermometer  tubing.     Do  not  try  tub- 
ing with  a  bore  smaller  than  one  millimeter. 

3.  The  essential  operations  to  learn  are  :  making  the  bulb,  filling 
it,  sealing,  and  making  a  graduating  scale. 

Suggested  Projects. 

I.     ARE    THE    FUELS   AT   HOME   COSTING     TOO    MUCH?      ARE    THEY 
USED  EFFICIENTLY? 

175 


i76 


FUELS  AND  THEIR  USES 


2.  TO  MAKE  AN  ORDINARY  SAFETY  MATCH. 

3.  TO    MAKE    A    FIRE    BY    PRIMITIVE    MEANS    WITHOUT    MATCHES, 
BURNING  GLASS,  OR  FLINT  AND  STEEL. 

4.  DIFFERENT  METHODS  OF  BUILDING  A  FIRE  AND  REGULATING 

IT  WHEN  BUILT. 

Sources  of  fuel.— Everybody  is  familiar  with  the  mate- 
rials used  commonly  as  fuels  such  as  coal,  gas,  oil,  wood, 

and  alcohol.  Most 
fuels  come  originally 
from  plants,  that  is, 
they  are  organic  in 
origin.  Coal,  which 
seems  like  rock,  is 
really  nothing  more 
or  less  than  gradually 
transformed  bodies 
of  dead  plants. 
Prints  of  leaves  and 
sometimes  whole 
trunks  of  trees  all 
now  transformed 
into  coal  are  found 
in  coal  mines. 
Specimens  of  them 

may  be  seen  in  our  museums.  Millions  of  years  ago  vegeta- 
tion became  collected  in  swamps,  sank  into  the  earth,  and 
other  materials  came  to  lie  over  this  mass  of  organic  matter. 
Then  came  pressure,  heat,  and  moisture  acting  together  on 
this  plant  material,  gradually  driving  off  some  of  it  and  leav- 
ing a  hard  substance  made  up  very  largely  of  the  element  car- 
bon. In  some  places  simitar  swamps  exist  now  and  are  called 
peat  bogs,  a  poor  kind  of  fuel  being  dug  from  them,  which, 


Coal  beds  in  the  earth. 


ECONOMY  AND  BURNING  VALUE  OF  FUELS      177 


after  drying,  may  take  the  place  of  coal  or  wood.  It  is  be- 
lieved by  many  scientists  that  petroleum  and  natural  gas 
are  also  formed  through  slow  chemical  changes  from  dead 
bodies  of  plants  and  animals  buried  millions  of  years  ago. 
Great  areas  holding  gas  and  oil  have  been  discovered  in 
different  parts  of 
the  United  States, 
the  largest  produc- 
tion coming  from 
Pennsylvania,  West 
Virginia,  Indiana, 
Texas,  California, 
Oklahoma,  and  Illi- 
nois. Mexico  has 
fields  of  great  value, 
and  oil  is  found  in 
paying  quantities  in 
other  parts  of  the 
world,  southern 
Russia  being  one 
of  the  richest 
areas. 

Economy  and  burning  value  of  different  fuels.  —  Wood 
is  used  the  world  over,  and  is  probably  used  now  in  more 
homes  than  any  other  fuel.  Hardwood,  such  as  hickory, 
oak,  maple,  or  beech,  burns  longer  and  gives  a  steadier  heat 
than  softwoods,  such  as  poplar,  hemlock,  or  pine,  but  soft- 
woods give  off  heat  more  quickly.  Coal  is  a  much  used 
fuel  in  our  eastern  homes,  soft  coal  being  used  more  where 
it  is  abundant.  Soft  coal  is  much  dirtier,  but  somewhat 
cheaper  than  hard  coal,  or  anthracite.  Coke,  which  is  coal 
from  which  certain  gases  have  been  removed,  is  valuable 

H.-WHIT.    CIV.    SCI.    IN   THE   HOME — 12 


In  an  oil  region. 


i78 


FUELS   AND   THEIR   USES 


for  a  quick  and  hot  fire.  Natural  gas,  where  abundant, 
is  both  cheap  and  an  excellent  fuel,  while  artificial  gas  has 
come  into  many  homes  to  be  used  as  an  ideal  fuel  for 
cooking.  Some  homes,  indeed,  have  come  to  use  elec- 
tricity, and  it  is  believed  by  scientists  that  when  our  great 
coal  and  oil  resources  have  been  exhausted,  we  shall  depend 
still  more  upon  electricity  produced  from  water  power  as  a 
source  of  heat  in  our  homes.  An  interesting  home  project 
would  be  a  study  of  the  costs  of  the  fuels  used  in  your 
own  home.  Fill  out  a  table  like  the  one  shown  below, 

FUELS   USED   IN   MY   HOME 


FUELS 

AMOUNT 

DATE  PURCHASED 

COST 

USE 

giving  the  kind  of  fuel,  the  amount  bought  on  each  date, 
and  for  what  purpose  the  fuel  is  used.  Is  it  more  econom- 
ical to  buy  in  small  or  large  quantities?  A  study  of  the 
second  table  on  a  comparison  of  fuels  shows  that  different 
fuels  have  a  very  different  heating  value,  but  as  their  cost 
in  the  different  localities  differs  so  greatly,  this  table  would 
have  to  be  modified  by  each  boy  and  girl  who  uses  it,  for 
his  own  locality. 

Heating  value  of  fuels.  —  It  is  of  some  interest  to  com- 
pare the  available  heat  produced  by  different  fuels.  In 
the  following  table  is  shown  the  amount  of  water  which 
can  be  heated  from  the  freezing  point  to  the  boiling  point 
for  one  cent  at  specified  prices,  provided  no  heat  is  lost. 
It  is  understood,  of  course,  that  no  heating  device  will 


WHAT  IS  IT  THAT  BURNS  IN  FUELS? 


179 


QUANTITIES   OF  HEAT   OBTAINED   FROM   VARIOUS   FUELS   FOR 
ONE    CENT 


FUEL 

PRICE 

Gallons  of  water  heated  from 
freezing  to  boiling  point  if 
no  heat  is  lost. 

Soft  wood 
Hard  wood 
Soft  coal 
Hard  coal 
Coke 
Charcoal 
Kerosene 
Natural  gas 
Manufactured  gas 

$15.00  per  cord 
1  6.  oo.  per  cord 
lo.oo  per  ton 
15.00  per  ton 
12.00  per  ton 
80.00  per  ton 
.20  per  gal. 
.50  per  looo  cu.  ft. 
1.50  per  1000  cu.  ft. 

14 
20 
17 
13 
13 

2.6 

4.1 
13 

2.8 

give  one  hundred  per  cent 
so  in  practice,  you  could 
boiling  point  as  is  indi- 
cated by  the  table  above. 

If  you  wish  to  heat 
only  a  kettle  full  of  water 
the  coal  range  gives 
much  less  efficient  serv- 
ice than  the  gas  range, 
even  though  gas  may 
cost  more  for  a  given 
number  of  heat  units. 
Do  you  see  why  this  is? 

What  is  it  that  burns 
in  fuels  ?  —  If  you  hold 
a  clean  glass  plate  in  the 
flame  of  a  candle,  you 
will  notice  a  thick,  black 
-deposit  gather  on  that 
part  of  the  plate  exposed 
to  the  flame.  This  ma- 


efficiency  in  the  burning  of  fuel, 
not  heat  as  much  water  to  the 


Carbon  from  a  candle. 


i8o 


FUELS   AND   THEIR   USES 


terial  is  almost  pure  carbon.     A  little  thought  must  con- 
vince one  that  it  comes  from  the  candle.     If  we  hold  a 

well-dried  funnel  over  the  candle 
flame,  we  find  drops  of  mois- 
ture on  the  inside  of  the  fun- 
nel. We  know  the  water  did 
not  come  from  the  air,  because 
no  water  settled  on  the  walls 
of  the  funnel  before  the  candle 
was  placed  under  it,  therefore 
we  conclude  that  a  burning 
candle  produces  water.  If  we 
now  make  some  hydrogen  gas  by 
pouring  a  little  hydrochloric  acid 
over  zinc,  and  then  pass  it 
through  a  drying  chamber  as 
shown  in  the  diagram,  we  can 
burn  the  gas  in  air.  Let  us  be- 
fore lighting  the  gas  allow  it  to 
pass  for  two  or  three  minutes 
into  a  dry,  cold  funnel.  Watch 
the  inside  of  the  funnel  carefully. 
Does  anything  happen?  Now 
light  the  colorless  gas  and  invert 
the  funnel  over  the  flame  as 
before.  You  will  notice  that 
water  appears  on  the  inside  of  the 
funnel.  Since  water  is  formed 


Water  is  a  product  of  burning  hy- 
drogen. 


both  by  the  burning  of  the  candle  and  the  burning  of  hydro- 
gen, it  appears  that  hydrogen  is  also  in  the  candle.  All  fuels 
contain  carbon.  Most  fuels  contain  carbon  and  hydrogen 
as  well,  and  many  contain  other  substances  in  addition. 


THE   KINDLING  TEMPERATURE 


181 


Experiment.  —  To  find  out  if  all  substances  take  fire  at  the  same  temperature. 

Materials:  Tin  plate  or  sheet  iron.  Sulphur.  Phosphorus.  Wood. 
Ring  stand.  Clamp.  Burner. 

Method:  Support  the  sheet  iron  horizontally  with  a  clamp  attached  to 
ring  stand.  Place  a  few  short  pieces  of  wood  (broken  match  stems) 
on  the  middle  of  the 
iron  plate,  and  two 
inches  distant  from 
this  place  on  one 
side  a  lump  of  sul- 
phur the  size  of  a 
pea,  and  on  the  other 
side  a  piece  of  phos- 
phorus the  size  of  a 
rice  grain.  (Do  not 
handle  phosphorus 
with  the  bare  hands 
and  always  cut  it 
under  water.)  Place  a  low  flame  under  the  middle  of  the  iron. 
The  iron  distributes  the  heat  so  quickly  that  we  may  assume  that 
all  the  materials  are  being  warmed  equally  at  the  same  time.  Each 
time  one  burns  we  may  turn  the  heat  on  a  little  stronger. 

Observations:  Note  the  appearance  of  smoke,  the  melting  of  the  sub- 
stances, and  the  order  of  taking  fire. 

Conclusion:  The  temperature  at  which  a  substance  takes  fire  is  known 
as  the  kindling  temperature.  What  does  this  experiment  show  you 
in  regard  to  kindling  temperatures  of  sulphur,  phosphorus,  and 
wood? 

The  kindling  temperature.  —  It  is  evident  that  different 
substances  take  fire  at  different  intensities  of  heat.  The 
intensity  or  degree  of  heat  is  called  temperature.  In  the 
experiment,  we  found  that  the  phosphorus  burns  first,  then 
the  sulphur,  while  a  much  higher  flame  is  necessary  to 
make  the  wood  burn.  Evidently  some  substances  kindle 
at  a  much  lower  intensity  of  heat  than  others.  If  we  now 
use  a  thermometer,  an  instrument  used  for  detecting  dif- 
ferent intensities  of  heat,  or  temperatures,  we  can  find  the 
exact  kindling  temperatures  of  many  substances. 


182 


FUELS  AND   THEIR  USES 


How  temperature  is  measured.  —  What  do  we  mean  by 
temperature?  We  are  aware  that  our  bodies  are  warm, 
and  that  ice  is  cold.  Measured  in  de- 
grees of  temperature,  the  body  is  98.6 
degrees,  while  melting  ice  is  32  degrees 
Fahrenheit.  The  common  house  ther- 
mometer is  an  instrument  consisting  of 
a  fine  bore,  sealed  glass  tube  with  a  bulb 
at  the  lower  end.  Mercury  or  colored 
alcohol  fills  this  bulb  and  extends  part 
way  up  the  tube.  As  heat  makes  mer- 
cury expand,  it  rises  in  the  tube  when 
it  gets  warmer,  and  degrees  of  temper- 
ature are  marked  on  the  thermometer 
(see  diagram).  There  are  two  kinds  of 
measurements,  the  one  used  by  scien- 
tists, known  as  the  Centigrade  scale, 
while  the  Fahrenheit  scale  is  used  in  this 
country  for  ordinary  purposes.  Ther- 
mometers have  come  into  very  general 
use,  and  we  should  all  know  how  to  read 
them  and  understand  what  they  mean.  They  are  useful 
as  regulating  devices  in  cooking,  as  we  often  find  them  in 
the  oven  doors.  We  also  use  them  for  regulating  the 
temperature  of  our  rooms.  The  room  temperature  should 
never  be  allowed  to  go  over  70  degrees  Fahrenheit  in  winter 


House  thermometer. 


Clinical  thermometer. 


and  the  air  should  not  be  allowed  to  get  dry,  as  such  con- 
ditions increase  our  liability  to  colds  when  we  leave  the 
house  to  go  out  of  doors.  One  type  of  thermometer  has 


HOW  TO  MAKE  A  FIRE  183 

become  a  household  necessity.  This  is  the  clinical  ther- 
mometer which  is  used  in  order  to  detect  any  change  in 
the  temperature  of  the  body  from  normal,  or  98.6  degrees. 
Body  temperature  changes  are  the  surest  indication  that 
something  is  wrong  within,  for  fever  always  shows  the 
presence  of  toxins  or  poisons  in  the  blood,  and  may  mean 
serious  illness.  In  case  of  a  high  temperature  or  fever  a 
physician  should  always  be  called. 

Study  of  a  match.  —  Fire  making  has  improved  greatly 
since  the  days  when  the  Indian  rubbed  a  pointed  stick 
into  a  hole  in  another  stick  in  order  to  obtain  a  light 
through  the  heat  evolved  by  the  rapid  rubbing  or  friction. 
The  flint  and  steel  of  our  forefathers  made  use  of  per- 
cussion in  obtaining  fire,  and  the  modern  friction  match 
makes  scientific  use  of  the  different  kindling  temperatures 
of  different  substances.  We  have  seen  that  phosphorus 
kindles  at  a  lower  temperature  than  most  substances,  but 
white  phosphorus  is  poisonous  and  its  use  in  making 
matches  has  been  prohibited  by  law,  so  that  the  ordinary 
match  head  now  contains  a  mixture  of  a  phosphorus  com- 
pound combined  with  potassium  chlorate,  powdered  glass 
or  sand,  and  glue.  By  rubbing  this  enough  heat  develops 
so  that  it. lights.  In  the  safety  match  the  head  is  made  up 
of  some  substance  that  burns  at  a  low  temperature  while 
red  phosphorus  is  placed  on  the  box,  combined  with  sand  or 
powdered  glass  to  give  it  a  rubbing  surface.  This  prevents 
the  match  from  being  lighted  without  the  phosphorus  on 
the  box  to  aid  it  in  its  ignition. 

How  to  make  a  fire.  —  The  following  simple  experiment 
will  show  one  factor  necessary  to  start  a  fire.  Cover  a 
burning  candle  with  a  lamp  chimney  so  that  it  is  closed 
at  the  bottom  but  open  at  the  top.  The  candle  gradually 


184 


FUELS  AND   THEIR  USES 


No  air  inlet ;  6,  No  air  out- 
let ;  c,  Has  both  inlet  and 
outlet.  This  gives  a  good 
draft. 


goes  out.  Now  cover  the  lamp  chimney  with  a  piece  of 
cardboard  and  bring  it  over  the  lighted  candle  again,  but 
leave  an  open  space  under  the  chim- 
ney. Again  the  candle  goes  out. 
Light  the  candle  and  place  the 
chimney  over  it,  leaving  the  chim- 
ney open  at  both  top  and  bottom. 
The  candle  burns. 

A  study  of  the  burner  of  a  kero- 
sene lamp  shows  that  air  passes  in, 
as  in  the  case  of  the  candle,  under- 
neath the  flame,  and  passes  up  out 
of  the  top  of  the  chimney.  By  holding  the  hand,  or  by 
placing  a  small  light  object  over  the  top  of  the  chimney, 
the  passage  of  air  is  noticed.  The  burner  of  a  lamp  regu- 
lates the  air  supplied  to 
the  flame,  which  goes 
out  if  the  air  supply  is 
cut  off,  as  was  shown  in 
the  case  of  the  candle. 
Evidently  a  current  of 
air  is  necessary  to  make 
fire  burn.  These  cur- 
rents which  are  in  circu- 
lation after  the  fire  starts 
are  known  as  convection 
currents,  and  as  we  shall 
see  in  a  moment,  are  im- 
portant factors  in  heat- 
ing our  homes.  In  order 
to  start  a  fire  in  the  kitchen  stove  or  open  fireplace,  we 
put  in  a  piece  of  paper  and  cover  it  with  some  shavings 


How  air  circulates  in  the  common  oil  lamp. 
(After  Clark.) 


THREE  METHODS  OF  DISTRIBUTING  ,HEAT      185 


or  fine  kindlings,  and  a  few  small  sticks  on  top  in  such  a 
way  that  air  can  circulate  around  the  fuel.  Light  the  paper 
at  the  bottom  and  the  fire  is  started.  If  we  were  to  shut 
off  the  upper  draft  in  the  pipe  by  closing  the  damper,  or 
if  we  were  to  close  the  lower  door  in  the  stove  so  as  to 
cut  off  the  current  of  air  from  below,  the  fire  would  smolder 
and  go  out.  Air  with  its  constant  supply  of  oxygen  is 
necessary  to  keep  a  fire  burning.  We  say  the  hot  air 
rises.  But,  as  a  matter  of  fact,  warm  air 
is  lighter  than  cold  air  and  the  cold  air  is 
pulled  downward  with  such  force  by  gravity 
that  the  warm  air  is  crowded  out  of  the 
way.  Thus  smoke  made  up  largely  of  hot 
gases  is  pushed  up  the  chimney. 

Three  methods  of  distributing  heat.  - 
We  have  all  seen  that  heated  currents  of 
air  are  carried  up  by  convection.  Thus  heat 
is  moved  about  in  the  room  by  means  of 
currents  of  air.  The  air  as  it  moves  gives 
heat  to  cooler  bodies,  and  thus  to  a  great  Coi}vection  currents 
extent  the  rooms  of  our  houses  are  warmed.  j£atear  vessel  of 
But  heat  also  moves  through  space  where 
there  is  no  air.  We  all  know  that  the  sun  keeps  us  warm, 
but  do  we  all  know  that  its  heat  travels  through  vast 
areas  of  space  in  which  no  air  exists  ?  This  space  is  filled 
with  ether,  and  through  the  ether  heat  moves  by  means 
of  waves.  This  method  of  heat  transference  is  called 
radiation.  Some  surfaces  absorb  heat  much  more  rapidly 
than  others.  Scientists  know  that  black  or  dull  sub- 
stances do  this  much  better  than  light  or  shiny  substances, 
and  substances  which  absorb  heat  readily  give  it  up 
easily  by  radiation.  May  this  be  a  reason  for  our  black 


1 86 


FUELS   AND   THEIR   USES 


stoves  and  dull  radiators?  Still  a  third  method  of  heat 
transference  is  the  passing  of  heat  from  one  particle  of 
material  to  another.  This  is  called  conduction.  A  very 
interesting  experiment  shown  in  the  figure  illustrates  this 
method  of  heat  transference.  The  heat  received  by  one 
set  of  particles  is  passed  on  to  others,  and  by  them  to 
still  others.  Most  metals  are  very  good  conductors.  Some 
substances,  like  glass,  water,  and  many  rocks,  are  fair  con- 
ductors, while  air,  wood,  paper,  and  linen,  silk,  and  woolen 
fabrics  are  poor  conductors.  This  principle  of  non-con- 
duction is  used  in  making  the  tireless  cooker,  the  thermos 
bottle,  and  the  ice  chest,  where  the  heat  is  kept  inside  in 
one  case,  and  outside  in  the  other.  Solids  are  the  best 
and  gases  the  poorest  conductors  of  heat,  air  being  one  of 
the  best  heat-insulating  (non-conducting)  materials.  Con- 
vection can  take  place  only  in  liquids  and  gases.  Remem- 
ber that  all  these  methods  of  transference  of  heat  are  at 
work  in  heating  our  homes. 


Experiment.  - 

Materials: 


-  To  see  if  heat  will  travel  along  a  metal  rod. 
A    metal    rod    15    to     20   inches    long.     Ring  stand   and 

clamp.    Burner.    Wax. 
Thread. 

Method:  Tie  a  short 
thread  to  each  of  six 
tacks.  Attach  these  two 
inches  apart  to  the 
metal  rod  by  means  of 
melted  wax.  Support 
the  metal  rod  so  that 
one  end  is  in  the  flame 
of  the  Bunsen  burner. 
Observation:  Notice  the 
order  of  the  melting  of 
the  wax  and  dropping  of  the  tacks.  What  does  this  suggest? 

Conclusion:  What  does  this  experiment  teach  about  conduction  of  heat? 


REFERENCE  BOOKS  187 

REFERENCE   BOOKS 

Allen,  Sweden  and  Safety  Matches.     Ginn  and  Company. 

Ashmead,  The  Man  Who  Mines  our  Coal.     Scientific  American,  May  18,  1918. 

Barber,  First  Course  in  General  Science,  Chapter  I.     Henry  Holt  and  Company. 

Clark,  Aft  Introduction  to  Science,  Chapters  I,  II,  IV.     American  Book  Company. 

Cleland,  Geology,  Physical  and  Historical,  Chapter  XVI  {For  teachers).     American 
Book  Company. 

Fall,  Science  for  Beginners,  Chapters  XI,  XXV.     World  Book  Company. 

Faraday,  Chemical  History  of  a  Candle.     Harper  Brothers. 

Forman,  Stories  of  Useful  Inventions:     The  Century  Company. 
—  The  Efficient  Use  of  Coal.     Century,  February,  1918. 

Greene,  Coal  and  the  Coal  Mines.     Houghton  Mifflin  Company. 

Ilodgdon,  Elementary  General  Science.     Hinds,  Hayden  and  Eldredge. 

Lynde,  Physics  of  the  Household,  Chapters  VIII,  IX,  X.     The  Macmillan  Com- 
pany. 

Maron,  The  Origin  of  Inventions  (Fire  making).     Charles  Scribner's  Sons. 

Mumper,  Text-Book  in  Physics.     Ameri  :an  Book  Company. 

Routledge,  Discoveries  and  Inventions  of  the  Nineteenth  Century,  pages  646-652. 
Routledge. 

Stone,  Making  a  Match.     General  Science  Quarterly,  Salem,  Mass.,  January,  1919. 

Tappan,  Makers  of  Many  Things  (Matches).     Houghton  Mifflin  Company. 

Toothaker,  Commercial  Raw  Materials  (Coal  and  Oil).     Ginn  and  Company. 

Van  Buskirk  and  Smith,   The  Science  of  Everyday  Life,  Project  II.     Houghton 
Mifflin  Company. 

Venable,  History  of  Chemistry  (For  teachers).     D.  C.  Heath  and  Company. 

Whitman,  How  to  Make  a  Thermometer.     General  Science  Quarterly,  May,  1920. 


CHAPTER  XII 
HEATING   OUR  HOMES 

Problems.  —  i.    To  see  how  our  homes  are  warmed. 

2.  To  find  out  how  heating  devices  are  constructed. 

3.  To  learn  the  best  way  of  regulating  the  fire  in  the  stove 
or  furnace. 

4.  To  see  how  heat  is  used  in  cooking. 

5.  To   understand   how   the   hot-water  supply  system  is 
operated. 

6.  To  learn  how  to  find  the  amount  of  gas  consumed. 

Experiments. 

1.  To  show  the  principle  of  hot- water  heating. 

2.  To  show  the  great  amount  of  heat  stored  in  £team. 

3.  To  show  how  to  produce  luminous  and  non-luminous  gas  flames. 

Project  I.  —  To  QUALIFY  AS  AN  EXPERT  HEATING  DEVICE  OPERATOR 

IN  MY  HOME. 

1.  To  start  fires  quickly  without  use  of  kerosene. 

2.  To  control  the  fire  properly:  to  keep  the  house  evenly  heated; 
to  have  the  oven  at  the  proper  temperature  at  the  right  time. 

3.  To  increase  the  humidity  of  the  air  when  needed,  and  to  secure 
ample  ventilation. 

4.  To  adjust  the  air  mixer  on  gas  burners. 

5.  To  clean  out  clogged  and  dirty  gas  burners. 

6.  To  prevent  needless  heat  loss  from  any  cause. 

7..   To  prevent  the  existence  of   fire  hazards  from  any  heating 
device. 

188 


HOW  HEAT  IS  USED  IN  OUR  HOMES 


189 


Project  II.  —  To  LEARN  HOW  MY  COAL  RANGE  is  CONSTRUCTED 

AND  HOW  TO  RUN  IT. 

Study  coal  range  at  home.  Find  out  what  the  different  parts  are 
for  and  how  they  are  related  to  each  other.  Make  a  cross  section 
diagram  across  the  fire  box  and  oven.  Use  arrows  to  show  circu- 
lation of  gases  from  room  to  stovepipe  when  oven  is  being  heated. 
Use  dotted  lines  to  suggest  necessary  passages  which  would  not 
show  in  cross  section.  Make  a  chart  like  the  one  below  and  fill 
in  the  blank  spaces,  indicating  how  you  would  regulate  fire  to  meet 
different  conditions.  Include  the  following  table  completed  in  your 
report  of  this  project. 


DRAFT  IN 
ASHPIT 
DOOR. 

(A) 

SLIDE  m 
FUEL  DOOR. 

(B) 

DAMPER  ON 
STOVEPIPE. 

(C) 

CHECK 
DRAFT  IN 
STOVEPIPE. 
CD) 

Starting  a  fire 

Keeping  a  moderate  fire    . 

Cooling  an  overheated  stove  .     . 

To  keep  a  fire  overnight    .     .     . 

Additional  Projects. 

I.  TO  DETERMINE  HOW  MUCH .  FUEL  CAN  BE  SAVED  BY  USING  A 
FIRELESS  COOKER  FOR  COOKING  CERTAIN  FOODS. 

2.  TO  UNDERSTAND  THE  HOT- WATER  SUPPLY  IN  MY  HOME. 

3.  TO    UNDERSTAND   HOW   HEAT   IS    TRAPPED    IN    A    SUN    PARLOR, 
AND  COLD  FRAME. 

Thought  Question. 

i.  Why  does  not  the  cold  water  enter  the  hot-water  tank  through 
a  pipe  at  the  bottom  of  the  tank  rather  than  through  the  one  from 
the  top  ? 

How  heat  is  used  in  our  homes.  —  Without  heat  for 
warming  our  houses  and  cooking  our  foods,  home  would 
be  a  dreary  place.  We  do  not  always  appreciate  the  hot, 
well-cooked  dinner,  warm  rooms,  and  the  cheerful  fireplace 


HEATING  OUR   HOMES 


because  these  things  have  long  been  commonplace.  Heat 
has  become  a  servant  of  man,  and  fire  is  harnessed  in 
many  ways  that  would  be  strange  to  our  forefathers.  As 
good  home  makers,  we  should  learn  about  the  devices  used 
for  heating  and  cooking  in  the  home. 

The  coal  stove.  —  The  ordinary  coal  stove  used  for 
heating  or  cooking  is  really  a  metal  box  arranged  so  as 
to  admit  air  for  combustion,  and  to  carry  the  products  of 


'Pilpe  to  C"KT-nxT\ey 
^"•^J  Check  Damper- 

-avH 


"Directive 


The  coal  range.     Point  out  the  place  for  the  check  draft. 

combustion  up  the  chimney.  The  coal  rests  on  the  grate 
and  is  burned  in  the  fire  box.  Below  the  grate  is  a  com- 
partment to  hold  ashes,  called  the  ash  pit.  Each  compart- 
ment has  a  door  with  openings  and  slides  in  it.  The 
openings  in  the  lower  door  form  the  draft,  and  those  in  the 
upper  door  the  check  draft.  In  the  stove  pipe,  which  leads 
to  the  chimney,  there  is  another  device  for  controlling  the 
air  currents  called  the  damper. 

Regulation  of  fire.  —  In  starting  the  fire,  the  lower  draft 
and  the  damper  should  be  open,  but  the  check  draft  should 
be  closed.  This  allows  the  poisonous  carbon  monoxide 


HOW  A  ROOM  IS  WARMED 


191 


which  comes  from  coal,  to  escape  up  the  chimney.  The 
hottest  fire  is  obtained  when  the  damper  and  draft  are 
both  open  and  the  check  draft  closed,  as  this  allows  a 
free  passage  of  air  through  the  burning  coal.  By  open- 
ing the  check  draft,  closing  the  draft,  and  partially  closing 
the  damper,  the  fire  will  burn  slowly.  By  closing  the 
damper  completely,  the  air  current  is  checked  and  burning 
almost  stops.  If  the  room  is  overheated,  close  the  draft, 
open  the  damper  and  the  upper  door  of  the  stove.  The 
air  from  the  room  will  then  rush  in  over  the  coal  and  pass 
up  the  chimney,  thus  cooling  the  stove  without  helping 
the  materials  to  burn.  In  checking  the  fire,  always  close 
the  draft.  If  the  draft  is  left  open  and  the  damper 
closed,  the  poisonous  gas,  carbon  monoxide,  may  escape 
into  the  room.  A  very  small  percentage  of  this  gas  in  the 
air  is  fatal.  Carbon  monoxide  has  no  odor  to  warn  of 
its  presence  and  people  have  been  suffocated  while  sleep- 
ing in  a  room  with  a 
stove  in  which  the 
fire  was  checked  in- 
correctly. 

How  a  room  is 
warmed.  —  In  the 
case  of  the  old- 
fashioned  fireplace, 
although  it  is  still 
used  because  of  its 
coziness  and  good 
cheer,  very  little 
heat  is  given  to  distant  parts  of  the  room,  most  of  the  heat 
going  up  the  chimney.  The  stove  transfers  to  the  room  by 
convection  and  radiation  about  seventy  to  eighty  per  cent 


Convection  currents  caused  by  a  hot  stove. 


IQ2 


HEATING  OUR  HOMES 


of  the  heat  obtained  from  the  fuel.  Air  coming  in  contact 
with  the  hot  surface  of  the  stove  expands  and  becomes 
lighter,  and  is  pushed  up  by  heavier  air,  which  comes  in  to 
take  its  place  (see  arrows  in  diagram).  These  warm  cur- 
rents of  air  become  cool  as  they  pass  by  the  windows  and 
cold  walls  and  other  surfaces  which  absorb  heat,  and  sink 

again  to  the  floor. 
Since  the  stove  is 
warmer  than  other 
objects  in  the  room, 
it  radiates  heat  to 
them;  heat  is 
brought  also  through 
the  metal  from  the 
inside  to  the  outside 
surface  by  conduc- 
tion. Thus  all  three 
methods  of  heat 
transference  are  used 
to  some  extent  in 
heating  a  room. 

The  hot-air  fur- 
nace. —  The  hot-air 
furnace  has  come 
into  general  use  and 
is  much  liked  because  it  does  the  work  of  several  stoves 
and  requires  no  more  attention  than  one.  The  furnace  is 
simply  a  large  central  stove  placed  in  the  cellar,  and  cov- 
ered with  a  metal  jacket,  from  the  top  of  which  metal 
tubes,  or  ducts,  lead  out  to  the  different  rooms  to  be 
heated.  Air  from  out  of  doors  is  brought  to  the  bottom 
of  the  space  between  the  fire  box  and  the  inclosing  jacket, 


A  hot-air  furnace. 


ADVANTAGES  AND  DISADVANTAGES  OF  HOT  AIR    193 

and  as  it  becomes  hot,  rises  and  passes  through  the  pipes 
to  the  various  rooms.  A  study  of  the  diagram  on  page 
192  shows  that  nearly  the  same  method  of  heat  transfer 
takes  place  in  the  furnace  as  in  the  case  of  the  stove. 

Regulation  of  the  air  supply.  —  It  is  well  to  remember 
that  air  when  heated  increases  in  volume  from  five  per 
cent  in  cool  to  over  twenty  per  cent  in  extremely  cold 
weather.  For  this  reason  less  cold  air  should  be  let  into 
the  furnace  through  the  cold  air  flue  in  very  cold  weather. 
The  small  slide  used  to  regulate  this  volume  of  air  (see 
S  in  diagram)  should  be  adjusted  according  to  the  weather 
outside,  otherwise  much  coal  may  be  wasted  in  order 
to  keep  the  rooms  warm.  Some  houses  have  a  system 
by  which  the  warm  air  after  circulating  through  the 
rooms  is  sent  to  the  furnace  to  be  warmed  again.  This 
is  more  economical  of  heat,  but  does  not  give  as  good 
ventilation. 

Advantages  and  disadvantages  of  the  hot-air  furnace.  — 
The  hot-air  furnace  is  less  expensive  to  install  than 
either  steam  or  hot  water,  is  easily  operated,  and  gives  up 
heat  quickly.  The  disadvantages  of  a  furnace  in  a  large 
residence  are  that  the  long  horizontal  pipes  do  not  take 
heat  to  the  distant  rooms  leading  against  the  force  of  the 
wind.  The  hot-air  furnace  heats  irregularly,  and  is  un- 
satisfactory on  days  when  there  is  a  strong  wind,  and  after 
it  becomes  old  gives  off  much  dust  and  some  gas  into  the 
house. 

Experiment.  —  To  show  the  principle  of  hot- water  heating. 

Materials:  Apparatus  shown  in  diagram. 

Method:  Fill  the  apparatus  with  water.  This  can  be  done  by  pouring 
water  into  the  tank  at  the  top  and  opening  the  clamp  at  the  top  of 
the  bent  tube  until  water  fills  both  tubes.  Close  the  clamp.  Drop  two 
or  three  crystals  of  potassium  permanganate  through  the  rubber  tube 

H.-WHIT.    CIV.    SCI.   IN   THE   HOME — 13 


194 


HEATING  OUR  HOMES 


into  the  glass  tube,  connect  the  tubes  and  fill  the  tank  partly  fullof 

water.     Open  the  clamp.     Heat  the  flask. 
Observation  and  Explanation:   Notice  all  changes.     Describe  everything 

that  happens.      Explain  what  parts  of  a  hot- water  heating  system 

are  represented  by  the 
different  parts  of  the  ap- 
paratus. 


The  hot-water 
heating  system.  - 
In  the  hot-water 
heating  system,  we 
have  a  combined 
furnace  and  boiler 
in  the  cellar,  radia- 
tors in  the  rooms, 
connecting  pipes  to 
bring  the  water  to 
the  radiators  and 
back  to  the  boiler, 
and  a  tank  known 
as  the  expansion 
tank  at  the  top  of 
the  house,  in  which 
the  water  may  rise 


Hot-water  heating  system  at  the  left,  and  apparatus  to 
illustrate  it  at  the  right. 


as  it  expands.  The  principle  of  heat  transfer  from  the  boil- 
ers to  the  radiators  is  that  of  convection.  The  water  in 
the  boiler  is  never  heated  to  the  boiling  temperature.  It 
enters  the  radiators  at  a  temperature  of  175  to  185  degrees 
Fahrenheit,  and  leaves  it  ten  degrees  colder.  This  differ- 
ence in  temperature  causes  the  water  to  grow  heavier,  and  is 
responsible  for  the  flow  through  the  pipes. 

How  a  room  is  wanned  by  hot  water.  —  As  soon  as  the 
hot  water  reaches  the  radiator,  heat  is  conducted  through 


STEAM  HEAT  IN  THE  HOME  195 

the  metal  to  the  outside  surfaces.  Air  coming  in  contact 
with  the  radiators  is  heated,  and  this  heat  is  given  to 
other  objects  in  the  room  by  convection,  while  some  heat 
is  radiated  directly  to  the  walls  and  objects  in  the  room. 
Thus  the  room  is  heated  by  convection  more  than  by 
radiation,  and  we  have  a  more  even  distribution  of  heat 
than  by  stove  or  by  steam.  One  drawback  to  the  hot- 
water  system  is  the  fact  that  in  the  sleeping  rooms  we 
cannot  cut  off  the  heat  without  danger  of  freezing  the 
water  in  the  radiator.  The  best  plan  for  those  who  like 
to  sleep  with  the  windows  open  is  to  cover  the  radiator 
at  night  with  a  heavy  blanket  or  some  good  non-conduct- 
ing substance. 

Advantages  and  disadvantages  of  hot  water.  —  This  is 
one  of* the  most  expensive  systems  to  install,  but  it  is  more 
economical  to  operate  than  the  hot-air  furnace  or  the  stove. 
With  it  the  rooms  may  be  kept  at  an  even  temperature, 
but  unfortunately,  if  the  water  gets  cold  it  takes  a  long 
time  to  warm  it  up.  As  the  system  provides  no  ventila- 
tion, we  must  secure  fresh  air  in  some  other  way.  An  ex- 
cellent system  is  the  combination  of  hot  water  and  hot  air, 
in  which  the  boiler  is  situated  in  the  top  of  the  furnace, 
and  the  water  thus  heated  is  passed  to  rooms  far  distant 
from  the  furnace. 

Steam  heat  in  the  home.  —  In  the  steam-heating  systems, 
the  parts  are  practically  the  same  as  in  the  hot-water 
system,  except  that  there  is  no  expansion  tank  and  the 
pipes  are  closed  throughout.  Steam  made  by  boiling  water 
passes  through  the  pipes  to  the  radiators.  In  the  radiators 
the  steam  condenses,  giving  off  its  load  of  heat.  The 
water  formed  by  this  condensation  leaves  the  radiator  and 
is  brought  back  to  the  furnace  again,  either  by  a  system 


ig6 


HEATING  OUR  HOMES 


of  return  pipes,  or  if  the  house  is  small,  it  may  return 
through  the  steam  pipe. 

Experiment.  —  To  show  the  great  amount  of  heat  stored  in  steam. 
Materials:  Calorimeter  (a  soup  can  will  do).     Flask.     One-hole  stopper 
and     tube.     Rubber     tubing.     Steam     trap.     Thermometer.     Ring 
stand.     Burner. 


Steam-heating  system. 

Method  and  Observation:  (a)  Weigh  the  calorimeter  half  full  of  cold 
water.  Record  the  temperature.  Boil  the  water  in  the  flask.  Con- 
nect the  steam  trap  and  when  the  water  is  boiling  put  the  free  end  of 
the  trap  into  the  cold  water.  Let  it  run  for  about  five  minutes.  Re- 
move the  trap.  Stir  well,  and  take  the  temperature.  Weigh.  What 
has  caused  this  increase  in  weight?  How  many  degrees  in  tempera- 
ture was  the  water  warmed  by  the  steam?  (b)  Fill  the  calorimeter 
again  with  the  same  quantity  of  cold  water  used  in  (a),  and  at  the 
same  temperature.  Pour  into  it  a  quantity  of  boiling  water  equal  in 
weight  to  that  of  the  steam  added  in  (a).  What  is  the  rise  in  tem- 
perature? 


PROTECTION  AGAINST  LOSS  OF  HEAT  197 

Conclusion:  Which  will  give  the  larger  quantity  of  heat,  a  given  weight 
of  water  at  the  boiling  point,  or  the  same  weight  of  steam  at  the  same 
temperature?  Which  is  hotter,  steam  or  boiling  water?  If  you  are 
not  sure,  make  a  test. 

Advantages    and    disadvantages    of    steam   heating.  - 

Although  less  coal  is  used  in  steam  heating  than  in  most 
other  systems,  no  ventilation  is  supplied  and  an  uneven 
temperature  is  produced,  the  room  sometimes  being  very 
hot  and  sometimes  very  cold.  One  needs  to  be  quite  an 
engineer  to  run  this  system  properly.  The  snapping  or 
pounding  in  the  steam  pipes  is  caused  by  what  is  known  as  a 
water  hammer,  which  is  produced  by  the  water  suddenly 
rushing  into  a  vacuum,  and  striking  .the  pipe  or  the  other 
water  there  a  hard  blow.  When  steam  in  the  steam-heating 
system  suddenly  comes  in  contact  with  the  cold  radiator, 
it  condenses,  and  a  vacuum  is  produced.  If  there  is  water 
in  the  pipes  with  pressure  behind  it,  that  is,  steam  coming 
from  the  boiler,  it  may  be  sent  through  this  vacuum  with 
great  speed,  and  made  to  strike  a  hard  blow  against  the 
metal  pipes.  The  remedy  is  to  admit  steam  slowly  when 
first  warming  up  the  cold  system.  Steam,  like  hot  water, 
has  an  advantage  over  the  hot-air  system  in  that  it 
carries  no  dust.  Because  of  the  high  temperature  of  the 
radiators,  they  need  to  be  only  about  two  thirds  of  the 
size  of  hot  water  radiators.  Steam  is  used  with  good  re- 
sults in  warming  large  buildings. 

Protection  against  loss  of  heat.  —  Much  heat  is  often 
lost  through  the  radiation  from  pipes  in  the  cellar.  A 
good  plan  is  to  have  these  pipes  covered  with  some  in- 
sulating substance,  so  that  the  heat  will  be  retained  and 
delivered  where  it  is  needed.  Much  leakage  of  cold  air  is 
often  found  around  windows  and  doors.  If  the  window 


198  HEATING  OUR  HOMES 

rattles,  you  can  be  sure  that  cold  air  is  leaking  into  the 
house.  One  way  to  prevent  this  is  by  placing  weather 
strips  along  on  the  outside  of  the  window  where  it  fits 
into  the  sash.  A  much  better  method  of  keeping  out  cold 
air  is  by  means  of  the  double  window.  Ventilation  may 
be  obtained  through  a  loose  pane  on  hinges  which  can  be 
opened  when  desired.  The  storm  door,  which  is  nothing 
more  than  a  double  door  sometimes  arranged  with  a  tiny 
antechamber  in  which  one  may  wait  while  the  inner  door 
is  being  opened,  is  another  means  of  keeping  out  much 
cold  air,  especially  where  there  are  high  winds. 

The  use  of  heat  in  cooking.  —  In  the  coal  range  we  have 
the  same  principle  as. the  coal  stove,  except  that  on  one 
side  of  the  fire  box  there  is  an  oven  separated  from  the 
outside  walls  of  the  stove  by  a  space.  Heat  is  circulated 
through  this  space  to  warm  the  oven.  A  knowledge  of  the 
drafts  and  dampers  is  necessary  in  order  to  heat  the  oven 
properly.  The  main  air  supply  enters  through  a  draft 
into  the  ash  pit  under  the  coal,  passes  through  the  layer  of 
hot  coal,  helps  it  to  burn,  and  the  hot  gases  coming  from 
the  burning  coal  pass  around  the  oven  and  escape  up  the 
stovepipe.  (Seep.  190.)  The  oven  damper,  if  raised,  causes 
these  gases  to  pass  around  the  oven  before  entering  the  stove 
pipe.  When  the  oven  damper  is  down,  the  hot  gases  pass 
directly  out.  What  would  you  do  to  cool  the  oven? 

The  oven  temperature.  —  We  can  control  the  oven 
temperature  by  regulating  the  size  of  the  fire,  by  the  use 
of  the  oven  damper,  and  by  opening  the  oven  door.  We 
must  remember  that  some  things,  such  as  roast  meats, 
require  a  high  temperature,  while  custard  requires  a  much 
lower  temperature.  The  accompanying  table  shows  some 
of  the  differences  in  temperature  for  cooking  different  foods. 


THE  GAS  RANGE 


199 


OVEN  TEMPERATURES  FOR  BAKING  VARIOUS  FOODS 


Searing  Roasts      .     .     .     500°  F 

Biscuit 450° 

Pies 400° 


Bread 35o°F 

Layer  Cake ....     300° 
Custard 250° 


Experiment.  —  How  to  produce  a  luminous  and  a  non-luminous  gas  flame. 

Materials:  Bunsen  burner.     Chalk  dust. 

Method  and  Observations:  Close  the  air  holes  near  the  base  of  the  burner. 

Light   the   gas.     Describe   the   flame.     Open   the   air  holes.     What 

change  in  flame  occurs?     When  you  have  a  clear  non-luminous  flame, 

blow  a    little   chalk 

dust    into    the    air 

holes.     Effect  on  the 

flame  ?    Place  a  piece 

of  heavy  white  paper 

down  over  the  lumi- 

nous   flame    for   an 

instant.   What  is  the 

product  ? 
Conclusion:  From  these 

results  try  to  give  a 

reason  why  the  gas 

flame     is    luminous 

when  no  air  is  mixed 

with    it.     What    is 

the  part    that   car- 

bon plays  in  a  lumi- 

nous flame?     What 

type    of    burner    is 

best  for  cooking  de- 

vices? 


Top  burner  of  the  gas  range. 


The  gas  range. 

In      many      homes 

where  gas  is   avail- 

able, the  gas  range 

has  supplanted  the  coal  or  wood  stove  for  cooking.     It 

is  not  only  quicker,  cleaner,  and  more  convenient,  but. 

especially  if  natural  gas  is  available,  it  is  much  cheaper, 


2OO 


HEATING   OUR  HOMES 


The  top  burners  have  a  tube  at  the  base,  in  which  are 
openings  for  the  entrance  of  air.  The  air  mixes  with 
gas  entering  the  tube,  and  the  mixed  gases  are  passed 
through  small  holes  in  the  burner  ring,  and  burned. 
This  burning  should  take  place  with  a  blue  flame.  If  too 
little  air  is  admitted,  the  flame  will  be  yellow,  and  soot  will 
collect  on  the  cooking  utensils.  The  burner  should  be 
kept  clean,  for  dirt  clogging  the  air  mixer  will  cause  smoke. 
The  burner  can  be  taken  off  and 
boiled  in  water  containing  washing 
soda,  and  small  particles  of  dirt  re- 
moved by  picking  out  with  a  fine 
needle  or  wire.  When  lighting  the 
oven  one  should  be  careful  first  to 
open  the  oven  door,  light  the  pilot 
flame,  and  then  turn  on  the  gas. 
A  gas  stove  should  have  a  stove 
pipe  to  carry  off  the  gases  into  the 
chimney  flue. 

The  hot-water  supply.  —  Hot 
water  has  become  almost  a  neces- 
sity in  houses,  in  the  country  as 
well  as  in  the  city.  The  hot-water 
supply  for  household  purposes  is 
obtained  by  the  use  of  the  hot- 
water  storage  tank  connected  to 
the  coal  range  or  independent 
Hot-water  supply.  heater.  In  the  range  the  water 

is  heated  by  means  of  a  pipe  passing  close  to  the  fire  box, 
and  then  running  to  the  boiler.  In  addition  a  gas  stack 
is  often  attached  to  the  tank.  In  this  the  gas  flame 
heats  a  coil  containing  cold  water,  the  rapidly  heated 


READING  THE   GAS  METER 


201 


water  rises  as  it  becomes  lighter,  and  passes  into  the  pipe  of 
the  hot- water  tank.  When  the  hot  water  is  drawn  from  the 
faucet,  a  supply  of  cold  water  enters  through  the  pipe  which 
enters  at  the  top  of  the  tank  and  extends  down  to  a  level  just 
above  the  top  of  the  heating  device.  In  the  instantaneous 
gas  heater,  the  gas  is  automatically  turned  on  and  lighted 
by  a  pilot  flame  when  the  faucet  is  opened.  The  water  is 
heated  as  it  passes  through  the  coiled  pipes  in  the  flame. 
Reading  the  gas  meter.  —  Since  gas  is  a  commodity  which 
is  delivered  to  our  homes,  we  should  learn  to  read  the  meters, 


CUBIC 


Recording  dials  of  gas  meter. 

so  as  to  be  able  to  know  how  much  gas  is  burned,  and 
whether  we  use  it  economically.  The  recording  device  of 
a  small  gas  meter  has  three  small  dials,  and  a  fourth  one 
still  smaller  on  top,  which  has  a  scale  registering  two  cubic 
feet.  Above  the  three  dials  are  marked  the  figures  100,000, 
10,000,  and  1,000,  and  the  face  of  each  dial  is  figured  from 
o  to  9.  When  the  gas  passes  through  the  meter,  the  hands 
revolve,  the  two  outer  ones  in  the  direction  of  the  hands  of  a 
clock,  and  the  inner  one  in  the  opposite  direction.  In  the 
illustration  the  100,000  dial  hand  is  between  5  and  6,  the 
10,000  between  5  and  6,  and  the  1,000  at  8.  This  means 


202 


HEATING  OUR  HOMES 


that  the  meter  stands  at  55800  cubic  feet.  The  last  time 
the  meter  was  read,  as  the  dotted  position  of  the  hands  shows, 
it  stood  at  54200.  Another  kind  of  meter  is  so  arranged 
that  a  certain  amount  of  gas  is  given  out  after  placing  a 
coin  in  a  slot  in  the  meter.  When  this  gas  is  exhausted, 
the  meter  automatically  cuts  off  the  supply  until  another 
coin  is  dropped  in.  One  may  easily  check  up  the  amount 
of  gas  which  can  be  used  before  the  supply  is  cut  off  by 
reading  the  special  index  controlled  by  the  coins  inserted. 

Other  fuels  used  in  the  home.  —  Many  people  who  do 
not  live  where  gas  is  piped  into  the  house,  use  the  blue 
flame  kerosene  or  gasoline  stoves.  In  these  stoves  the 
fuel  flows  from  a  reservoir  down  to  a  wick  in  the  burner, 
where,  as  the  metal  becomes  heated,  the  fuel  evaporates, 
mixes  with  air  and  burns  in  the  same  manner  as  does  the 
gas  in  the  gas  stove.  In  practically  all  stoves  using  kero- 
sene or  gasoline  the  blue  flame  is  produced  in  this  way. 
Alcohol  is  sometimes  used  as  a  fuel  where  a  hot  flame  is 
needed  for  a  short  time,  as  with  the  chafing  dish,  and 
most  of  us  have  used  "  solidified  alcohol "  which  now 
comes  in  convenient  tins  for  use  at  any  time.  In  this  form 
of  fuel  the  alcohol  is  absorbed  in  a  soft  wax  or  paraffin. 
It  must  be  kept  from  the  air,  however,  or  it  will  lose  the 
burning  properties  quickly  through  evaporation. 

SCORE  CARD.    HEAT  IN  MY  HOME 


FAIR 

MY  5 

>CORE 

Total 

WARMTH 

All  parts  of  home 
warm  enough  in 
coldest     weather 

All    parts   of    each 
room      can      be 
evenly  heated  (5) 

Some     rooms     not 
warm  enough  in 
coldest     weather 
(4) 
Some  rooms  evenly 
heated;   others 
not  (3) 

Temperature  in  all 
rooms  too  cold  in 
coldest     weather 
(o) 
Unequal  heating  in 
all    rooms,    none 
comfortable      i  n 
every  part  (o) 

SCORE  CARD 


203 


SCORE   CARD.     HEAT   IN    MY   HOME  —  Continued 


MY  SCORE 

T?     yi 

FAIR 

VERY  POOR 

HiXCELLENT 

TOTAL 

VENTILA- 

Large    supply     of 

Small  supply  of  air 

No  air  in  heating 

TION   AND 

fresh    air    circu- 

circulated in 

circulation  (o) 

PROTEC- 

lated in  rooms  (2) 

rooms  (i) 

.... 

TION 

All  pipes  and  fur- 

Pipes but  not  fur- 

No   protection    of 

AGAINST 

nace       protected 

nace       protected 

pipes  or  furnace 

LOSS   OF 

against    loss     of 

against  heat  loss 

(o) 

HEAT 

heat  (2) 

(i) 

.... 

Weather    strips, 

Weather  strips  old, 

No  weather  strips, 

storm  doors,  and 

storm       doors 

storm    doors,    or 

storm      windows 

leaky,  storm  win- 

sashes.    Win- 

new    and     tight 
ventilation  sashes 

dows        without 
ventilation  sashes 

dows     rattle     in 
wind  and  leak  air 

in  windows  (6) 

(o) 

\o  / 

ECONOMY 
OF   FUEL 

Fuels   (except  gas) 
purchased  in 

Fuels  purchased  in 
small    quantities 

Very  small  quanti- 
ties purchased  as  : 

large     quantities 
at  one  time  (4) 

as:     i    gal.    oil; 
J  ton  coal  (2) 

i  qt.  oil;    i  bag 
coal;   i  bu.  wood 

(o) 

Wood,  coal,  coke,  or 

Artificial   gas   used 

No  saving  attempt- 

natural  gas  used 

sometimes    when 

ed    by    using 

in  kitchen  in  win- 

have coal  or  wood 

cheaper  fuels  (o) 

ter  (2) 

fire  (i) 

Fuel     not     wasted 

Fuel  often  saved  by 

No   attention   paid 

in  ashes  or  more 

attention   to   gas 

to  economical  use 

gas  burned  than 

burner    and    ash 

of  gas  or  to  ashes 

needed  (2) 

sifting  (i) 

(o) 

Electric    heat    sel- 

Electric heat  often 

Electric  heat  com- 

dom used  (2) 

used  (i) 

monly  used  (o) 

ECONOMY 

No    extra   dust   in 

Little  extra  dust  in 

Much  extra  dust  in 

IN  TIME 

winter  (3) 

winter  (i) 

winter  (o) 

AND 

No  ashes  (electric- 

Little    ash     or 

Much  ash  or  clink- 

WORK 

ity  or  gas)  (3) 

clinker  (2) 

er  (o) 

DONE 

Not  more  than  15 

Not  more  than  30 

More  than  30  min. 

min.  required  per 

min.  required  for 

a  day  required  for 

day    for    proper 

care    of    heating 

care    of    heating 

care    of    heating 

devices  (i) 

devices  (o) 

devices  (2) 

Thermostats    and 

Lacks   either    ther- 

No thermostats  or 

other  heat  regu- 

mostats  or   heat 

heat     regulating 

lating   apparatus 

regulating   appa- 

apparatus (o) 

so    that    furnace 

ratus  (i) 

can  be  regulated 

without  going  to 

cellar  (2) 

COOKING 

Cooking  stove 

Cooking  stove 

Cooking  stove 

makes  no  dust  or 

makes  little  dust 

makes  much  dust 

dirt    (electricity) 

or  dirt  (gas,  ker- 

or    dirt     (wood, 

(2) 

osene)  (i) 

coal)  (|) 

.... 

Stove  safe  (2) 

Stove     moderately 

Stove  not  safe  (o) 

safe  (i) 

Stove  easy  to  man- 

Stove    moderately 

Stove    difficult    to 

age  (3) 

easy    to   manage 

manage  (o) 

(2) 

Cooks    and    bakes 

Cooks  well;    bakes 

Cooks    and    bakes 

well  (3) 

poorly  (i) 

poorly  (o) 

GRAND   TOTAL 

204  HEATING  OUR  HOMES 

REFERENCE  BOOKS 

Barber,  General  Science,  Chapter  II.     Henry  Holt  and  Company. 
Burns,  Story  of  Great  Inventions.     Harper  and  Brothers. 

Butler,  Household  Physics,  Chapters  on  Heat,  pages  6-57.     Whitcomb  and  Barrows. 
Caldwell  and  Eikenberry,  General  Science.     Ginn  and  Company. 
Clark,  An  Introduction  to  Science,  Chapters  I,  II,  III.    American  Book  Company. 
Hopkins,  Experimental  Science  (For  help  in  projects).     Munn  and  Company. 
Lunt,  An  Illuminating  Gas  Project.     General  Science  Quarterly,  May,  1917. 
Lynde,  Physics  of  the  Household,  Chapters  VII,  XI.     The  Macmillan  Company. 
Mowry,  American  Inventions  and  Inventors.     Silver,  Burdett  and  Company. 
Smith  and  Jewett,  Introduction  to  the  Study  of  Science,  Chapter  II.     The  Mac- 
millan Company. 

Walrath,  Hot  Water  Boiler  Demonstration.    General  Science  Quarterly,  Jan.,  1918. 
Williams,  How  It  Works,  pages  386-391.     Nelson  Company. 
Williams,  Introductory  Fire  Lesson.     General  Science  Quarterly,  May,  1917. 


CHAPTER   XIII 
FIRE   PREVENTION    IN   THE   HOME 

Problems.  —  i.    To  learn   the  estimated  fire  loss  in  the 
United  States, 

2.  To  discover  the  usual  sources  of  fires. 

3.  To  understand  why  "fire  prevention  "  is  so  important. 

4.  To  learn  the  principles  underlying  the  putting  out  of 
fires. 

5.  To  see  how  home  fire  extinguishers  are  constructed 
and  used. 

Experiments.  —  i .   To  show  how  spontaneous  combustion  takes  place. 
2.  To  show  how  to  extinguish 

(a)  Burning  fat. 

(6)  Gasoline. 

Project  I.  —  To  REMOVE  THE  FIRE  HAZARDS  FROM  MY  HOME. 

1.  This  requires  a  good  knowledge  of  fire  dangers  and  the  most 
common  sources  of  fires. 

2.  Thorough  study  of  the  home  with  reference  to  the  possibility 
of  fire  should  be  made. 

3.  Fire  dangers  must  be  removed  by  appropriate  methods. 

4.  A  complete  report  will  include  a  discussion  of: 

a.  Principles. 

b.  Conditions  found. 

c.  Changes  made. 

Suggested   Project.    To  MAKE   A  TOY   CHEMICAL  FIRE   EXTIN- 
GUISHER. 

205 


206  FIRE  PREVENTION  IN  THE  HOME 

Fire  and  its  dangers.  —  You  may  have  been  fortunate 
enough  never  to  have  lost  your  home  or  loved  ones  through 
fire,  but  nevertheless  that  danger  is  always  with  us.  It 
stands  ready  for  the  careless  moment  when  you  give  it  an 
opportunity  to  burst  forth  with  its  suffocating  and  deadly 
flames,  and  many  are  its  victims.  Every  week  the  papers 
have  accounts  of  destruction  and  suffering  caused 
by  fire.  Read  the  following  clippings  selected 
from  a  paper  in  one  week : 

"  Mrs.  Laura ,  33  years  old,  of  66 Street,  died  in  the 

Southside  Hospital  to-day  from  burns  suffered  when  she  attempted 
to  hurry  a  fire  hi  the  kitchen  stove  by  pouring  oil  over  it." 

"  Florence  S. ,  three  years  old,  of  Avenue,  died  early 

to-day  in  the  General  Hospital  from  burns  received  yesterday,  when 
her  clothing  was  ignited  from  a  firecracker." 

"  Dozens  of  lives  were  imperiled  in  a  fire  which  destroyed  the 

apartments  at  Avenue  early  this  morning.  Some  occupants 

were  carried  out;  others  jumped  from  the  second  story  window; 
three  are  confined  in  the  hospital.  The  damage  was  $4000." 


Here  was  a  financial  loss  great  enough  to  have 
bought  each  one  of  you  in  the 
class  two  bicycles,  a  pair  of 
skates,  skis,  and  a  good  sled. 

"  Fire  which  threatened  to  wipe  out  a 
big  section  of  Homestead  caused  damage 
of  upwards  of  $45,000.  High  winds  car- 
ried sparks  and  several  other  fires  were 
started.  Fires  were  only  extinguished 
after  aid  arrived  from  surrounding  bor- 
oughs." 

The  money  loss  in  this  fire 

necessary.    (After  Richman.)  WOUld  have  bought  each  One 

of  the  pupils  in  your  class  an  automobile.  If  reports 
of  fires  which  have  occurred  in  the  entire  United  States 
in  the  last  twenty-four  hours  could  be  laid  on  your  desk 


ENORMOUS  FIRE  LOSSES 


207 


you  would  have  a  collection  of  about  fifteen  hundred. 
Records  of  past  years  show  that  the  number  of  fires 
averages  about  fifteen  hundred  a  day ;  one  every  minute. 

Enormous  fire  losses.  —  The  fire  loss  in  the  United 
States  for  1919  was  '$325,000,000.  There  were  in  the 
United  States  during  1919  over  5,000,000  fires.  Sup- 
pose these  fires  spread  at  equal  intervals  of  time,  and  the 


•$2.10 


Relative  per  capita  fire  losses  in  different  countries. 

fire  loss  was  distributed  evenly  throughout  the  year, 
then, 

Every  second  $10.00  in  property  is  destroyed. 

Every  minute  a  new  fire  starts  somewhere  in  the  United 
States. 

Every  hour  two  lives  are  lost  and  seven  persons  are 
injured  through  fire. 

Every  day  enough  property  value  is  destroyed  by  fire 
to  feed  and  clothe  a  city  of  50,000  people  for  ten  days. 

Every  week  the  fire  loss  is  enough  to  build  100  miles  of 
good  macadam  road. 

Every  month  the  loss  from  fire  is  equivalent  to  a  sum  of 
money  which  would  buy  the  grounds,  erect  the  buildings, 


208  FIRE  PREVENTION  IN  THE  HOME 

and  provide  an  endowment  to  pay  the  running  expenses 
of  a  large  college. 

In  a  year,  the  money  value  of  fire  losses  would  pay 
salaries,  books,  and  supplies  for  all  public  education  in  the 
entire  United  States  for  more  than  half  a  year. 

Charles  W.  Baker,  in  an  address  entitled  "  A  Street  of 
Desolation,"  said  in  speaking  of  the  damage  done  in  a 
single  year  that  "  the  buildings  consumed,  if  placed  on 
lots  of  65  feet  frontage,  would  line  both  sides  of  a  street 
extending  from  New  York  to  Chicago.  A  person  jour- 
neying along  this  street  of  desolation  would  pass  in  every 
thousand  feet  a  ruin  from  which  an  injured  person  was 
taken.  At  every  three  quarters  of  a  mile  in  this  journey 
he  would  encounter  the  charred  remains  of  a  human  being 
who  had  been  burned  to  death." 

Why  are  there  so  many  fires  ?  —  Are  these  losses  by 
fire  necessary?  What  causes  the  fires?  Many  fires  are 
reported  as  "  cause  unknown,"  but  a  study  of  the  causes 
in  a  large  number  of  other  cases  shows  that  the  principal 
cause  of  fires  is  CARELESSNESS.  No  one  of  us  can  truth- 
fully say  that  he  has  not  been  careless  about  such  mat- 
ters. It  is  time  that  we  begin  a  new  era  of  thoughtful, 
careful  attention  to  the  ways  and  means  of  safeguard- 
ing the  home,  the  business  houses,  and  the  factories 
against  fire. 

Sources  of  fires  in  the  home.  —  The  cause  of  about  90% 
of  the  fires  is  carelessness  in  regard  to  a  few  things  about 
the  home.  Some  of  the  most  important  things  about 
which  we  ought  to  be  more  careful  are : 

a.  The  use  of  kerosene  and  gasoline. 

b.  Matches  and  all  uncovered  flames. 

c.  The  heating  plant,  stove  pipes,  and  chimney. 


FLAMES  FOR  LIGHT 


209 


d.  Electrical  devices  and  wiring. 

e.  Oily  rags  and  other  rubbish. 

Matches.  —  In  the  United  States  half  a  million  flames 
are  produced  with  matches  on  an  average  every  minute. 
Every  bare  flame  has  the  possibilities  of  serious  conse- 
quences. Our  chief  concern  in  the  house  as  regards  matches 
is  to  keep  them  away  from  children  who  are  too  young 
to  realize  the  danger,  and  from  rats  and  mice,  which  are 
known  at  times  to  cause  fires  by  gnawing  the  match  heads. 
Nearness  to  heated  pipes  or  flues  at  times  ignites  matches. 
Protection  against  ani- 
mals is  secured  by  in- 
closing in  a  covered 
metal  or  earthenware 
box.  This  will  also 
smother  the  flame 
quickly  if  set  on  fire 
from  a  near-by  source 
of  heat.  Placing  on  a 
high  shelf  or  in  a  locked 
closet  or  drawer  is  usu- 
ally sufficient  protection 
against  the  small  child. 

Flames  for  light.  - 
The  candle,  kerosene 
lamp,  and  gas  flame  are 
common  sources  of  dan- 
ger in  the  home.  The 
candlestick  and  lamp  should  have  a  low  center  of  gravity  and 
a  broad  base  to  guard  against  tipping  over.  Unprotected 
paper  or  cloth  shades  for  candles  are  extremely  dangerous. 
A  mica  chimney  should  separate  the  flame  from  the  shade. 

H.-WHIT.    CIV.   SCI.   IN   THE   HOME  —  14 


Which  lamp  is  the  greater  fire  hazard  ? 


2IO 


FIRE   PREVENTION   IN   THE   HOME 


The  danger  from  lamps  comes  largely  from  leaving  them 
for  a  time,  from  dropping  them  when  carrying  them  about, 
and  from  filling  them  when  lighted.  Never  leave  a  burn- 
ing lamp  in  a  room  by  itself  for  any  length  of  time.  Use 
only  lamps  with  metal  reservoirs.  Always  fill  lamps  by 
daylight.  Keep  the  lamp  always  in  good  order.  Obser- 
vation of  these  simple  rules  will  do  much  to  prevent  serious 
fires. 

Fire  dangers  from  heating  devices.  —  Disastrous   fires 
from   chimneys,    stoves,    furnaces,    and   portable   heaters 

are  common.  Perhaps  most 
deaths  from  burning  come 
from  kindling  fires  in  the 
stove.  Match  heads  or 
lighted  kindlings  set  the 
clothing  on  fire.  Scarcely 
a  week  goes  by  that  you 
cannot  find  in  the  papers  an 
account  that  some  one  who 
used  kerosene  to  kindle  the 
fire  was  seriously,  if  not 
fatally,  burned.  Kerosene 
burns  so  easily  it  is  never 
safe  to  use  it  for  starting  a 
fire.  Hot  stovepipes,  the 
heater  itself,  or  hot  air 
ducts,  if  close  to  woodwork, 
are  fire  hazards.  Ashes  are  never  safe  when  left  loose  on 
the  cellar  floor,  or  in  wooden  receptacles.  Metal  con- 
tainers are  the  only  safe  ones. 

Miscellaneous  sources  of  fire.  —  All  celluloid  articles 
contain  oxygen  necessary   for  combustion  within   them- 


She  had  used  kerosene  oil  to  start  her  fire 
432  times  without  harm.  The  picture 
shows  what  happened  on  the  433d  time. 


GASOLINE  IS  TREACHEROUS  211 

selves.  On  this  account  celluloid  burns  quickly  and 
cannot  be  extinguished  by  smothering.  Hot  air  from  a 
register  will  sometimes  ignite  celluloid.  Make  a  list  of 
celluloid  articles  in  your  home. 

Spontaneous  combustion  is  a  frequent  cause  of  disastrous 
fires.  Certain  oils,  as  linseed  oil  used  by  painters,  absorb 
oxygen  in  drying.  By  this  process  heat  is  generated. 
If  the  oil  is  on  poor  heat  conducting  materials,  as  rags  and 
cotton  waste,  the  heat  may  increase  enough  to  reach  the 
kindling  point  of  the  materials  and  fire  results.  This 
usually  happens  when  nobody  is  around  and  so  the  fire 
makes  good  headway  before  it  is  discovered. 

Experiment.  —  To  show  how  spontaneous  combustion  takes  place. 
Materials :  Carbon  disulphide.     Phosphorus.    Test  tubes.    Filter  paper. 
Ring  stand. 

Method :   Dissolve  a  piece  of  phosphorus  the  size  of  a  pea  in  half  a  test 
tube  of  carbon  disulphide. 

( Note :  Do  not  handle  phosphorus  with  bare  fingers.  Phosphorus  and 
carbon  disulphide  are  both  inflammable.)  Wet  the  filter  paper  with 
this  solution  by  rolling  it  up  and  inserting  it  into  the  test  tube.  Open 
the  paper  and  expose  it  to  the  air  on  a  ring  stand.  As  the  carbon 
disulphide  evaporates  the  phosphorus  oxidizes  and  generates  heat. 

Observation  and  Conclusion :  What  happens  ?    Was  heat  generated  faster 
than  it  could  be  carried  off?     Explain  just  how  the  fire  occurred. 

Burning  fat  or  oils  used  for  frying  on  the  stove  are  not 
serious  dangers  as  they  can  be  smothered  easily  with  a 
cover  or  a  heavy  rug.  Trying  to  carry  the  burning  fat 
to  the  sink  is  dangerous.  A  few  drops  spilled  may  set  fire 
to  other  things.  The  addition  of  water  will  scatter  the 
burning  drops  and  spread  the  fire. 

Gasoline  is  treacherous.  —  It  is  a  safe  rule  never  to  clean 
with  gasoline  indoors,  and  never  keep  gasoline  in  a  glass 
bottle.  There  are  other  liquids  easily  obtainable  which 


212  FIRE   PREVENTION   IN   THE   HOME 

will  not  burn,  but  which  will  clean  just  as  well  as  gasoline. 
These  can  be  bought  at  the  drug  store.  They  are  safe. 
Use  them. 

Extinguishing  fires.  —  Since  a  fire  requires  oxygen, 
fuel,  and  a  temperature  above  the  kindling  point,  if  you 
deprive  a  fire  of  any  one  of  these  three,  it  will  be  extin- 
guished. There  are,  then,  three  possible  ways  to  put  out 
a  fire :  by  smothering,  by  removing  the  fuel,  and  by 
cooling. 

Smothering.  — Smothering  is  the  process  of  keeping  oxy- 
gen of  the  air  away  from  the  burning  substance.  With 
the  exception  of  a  few  substances  smothering  is  an  effec- 
tive way  of  extinguishing  a  small  fire.  A  woolen  blanket, 
rug,  or  coat  is  better  than  one  made  of  cotton  because  it 
is  less  inflammable.  The  blanket  is  much  more  effective 
wet  than  dry,  but  it  may  be  used  dry.  Another  way  to 
smother  a  flame  is  by  setting  free  a  non-combustible  gas 
about  the  flame  which  will  push  the  air  away  and  ex- 
tinguish the  fire.  This  is  sometimes  done  with  the  follow- 
ing chemicals :  carbon  dioxide,  ammonia,  carbon  tetra- 
chloride,  and  water  in  the  form  of  steam.  Substances 
like  celluloid,  and  explosives  which  contain  sufficient 
oxygen  for  combustion,  cannot  be  extinguished  in  this 
way. 

Removing  fuel.  —  It  is  often  possible  to  remove  the 
combustible  material  from  the  vicinity  of  the  flame  and 
thus  extinguish  it  in  a  short  time.  Covering  combustible 
material  by  banking  with  sand  and  trenching  to  remove 
fuel  are  practiced  in  brush  and  grass  fires.  Back  firing  in 
forest  fires  utilizes  the  principle  of  fuel  removal,  as  does  the 
dynamiting  of  buildings  in  the  path  of  the  fire  in  a  large 
city  conflagration.  ^ 


THE  HAND  CHEMICAL  EXTINGUISHERS          213 

Cooling.  —  Water  is  the  most  universal  fire  extin- 
guisher. It  has  many  properties  which  favor  its  use. 
It  can  be  thrown  long  distances  in  a  steady  stream. 
It  is  non-combustible.  One  pound  of  it  has  greater 
cooling  effect  than  the  same  weight  of  any  other  sub- 


water,  our  best  fire  extinguisher. 

stance.  On  changing  to  steam  it  increases  1700  times 
in  volume.  The  change  from  liquid  to  steam  absorbs  a 
large  amount  of  heat,  thus  adding  to  its  value  as  a  cool- 
ing agent.  The  steam  also  tends  to  smother  the  fire  by 
excluding  air. 

The  hand  chemical  extinguishers.  —  The  carbon  tetra- 
chloride  and  the  carbon  dioxide  extinguishers  are  two  types 


214  FIRE   PREVENTION  IN  THE  HOME 

of  chemical  extinguishers  suitable  for  use  in  the  house, 
the  school,  and  the  shop  when  the  fire  is  small. 

Experiment.  —  How  to  extinguish  (a)  burning  fat;  (b)  burning  gasoline. 

Materials:  Lard.    Gasoline.     Evaporating  dish.     Ring  stand.     Heavy 

cloth.     Carbon  tetrachloride.      Test  tubes. 

Method  and  Results :  (a)  Heat  a  teaspoonf ul  of  lard  in  an  evaporating  dish. 
When  smoking  hot  let  two  or  three  drops  of  water  fall  into  it.  Would 
water  be  a  good  substance  to  extinguish  burning  fat?  Wet  the  cloth 
and  carefully  lay  it  over  a  dish  of  burning  fat,  excluding  all  air. 

(&)  Pour  a  tablespoonful  of  gasoline  into  the  small  evaporating  dish. 
Set  it  on  fire.  Pour  water  from  the  test  tube  into  it.  Is  the  fire 
extinguished?  Smother  with  a  cloth.  Pour  this  out  and  use  another 
tablespoonful  of  gasoline.  Set  it  on  fire.  Pour  carbon  tetrachloride 
into  it  from  a  test  tube.  Result? 

(N.ote:  Carbon  tetrachloride  is  non-inflammable  and  evaporates  as 
easily  as  gasoline.) 

Conclusion:  What  advice  would  you  give  for  extinguishing  burning  fats 
and  gasoline  ? 

The  carbon  tetrachloride  extinguisher  holds  about  a  pint 
of  volatile  liquid  in  a  small  container  to  which  a  force 
pump  is  attached.  When  the  container  is  opened  and  the 
pump  worked,  a  stream  of  liquid  may  be  thrown  upon  a 
near-by  blaze.  The  liquid  changes  to  gas,  which  smothers 
the  flame.  When  this  extinguisher  is  used  take  care  not 
to  breath  the  fumes  given  off  for  they  are  harmful  and  in 
a  number  of  instances  have  proved  fatal.  This  type 
of  extinguisher  is  particularly  valuable  for  extinguishing 
small  gasoline  and  oil  fires.  Water  cannot  be  used  for 
these  fires  since  the  oil  or  gasoline  would  rise  to  the  surface 
of  the  water  and  continue  to  burn. 

The  small  carbon  dioxide  extinguisher  holds  2\  gallons 
of  water,  in  which  are  dissolved  i^  pounds  of  baking  soda 
and  a  bottle  containing  4  oz.  of  strong  sulphuric  acid  is 
suspended  above  the  solution.  When  the  extinguisher 


SAFETY  FIRST 


2IS 


is  inverted,  the  acid  mixes  with  the  soda  and  produces 
carbon  dioxide  gas.  The  gas  is  confined  and  creates 
such  great  pressure  that  the  liquid  is  forced  out  the  hose 
to  a  distance  of  40  to  50  feet.  The  water  which  escapes 
is  charged  with  carbon  dioxide  and 
has  some  soda  in  it.  All  these  sub- 
stances are  good  fire  extinguishers. 
The  flow  of  liquid  may  be  stopped  at 
any  instant  by  inverting  the  extin- 
guisher. But  after  once  inverting,  it 
must  be  recharged  at  once.  This  is 
the  kind  of  extinguisher  for  the  house, 
since  the  suffocating  gas  is  less  than 
in  case  of  the  volatile  gas  extin- 
guisher which  is  used  in  the  garage. 

Safety  first.  —  If  you  get  caught  in 
a  burning  building  and  the  fire  has 
made  such  headway  as  to  be  a  serious 
menace  to  you,  it  is  your  first  duty 
to  save  your  life.  It  is  well  to  be 
prepared  for  any  emergency  and  to 
know  in  advance  just  what  to  do. 
Do  you  know  where  the  stairs  are? 
The  fire  escapes?  If  it  is  necessary  Section  of  a  carbon  dioxide 

.-i  i  i        f-,1     i  extinguisher. 

to  pass  through  a  smoke-filled  room, 
tie  a  wet  cloth  over  the  nose  and  mouth  to  absorb  the 
smoke  and  crawl  on  the  floor  as  there  is  less  smoke  near 
the  floor.  If  you  think  you  must  jump  from  a  window, 
throw  out  pillows,  cushions,  and  mattress  to  land  on 
and  jump  only  if  forced  to  it.  Bed  clothing  may  be  tied 
into  a  rope  on  which  to  climb  to  safety.  Above  all  keep 
cool. 


2l6  FIRE   PREVENTION   IN  THE  HOME 

Scoring  fire  hazards.  —  Score  your  fire  hazards  rigidly 
and  then  go  carefully  over  your  list  to  see  what  changes 

you  can  make  at  once 
to  improve  conditions. 
If  the  matter  is  outside 
your  own  control  talk  it 
over  with  other  people 
and  get  their  advice  as 
to  how  best  to  do  away 
with  the  hazard.  We 
should  all  work  together 

The  best  air  in  a  burning  house  is  near  the  floor.      t()  prevent  unnecessary 

fires.  A  rather  different  score  card  could  be  made  by  boys 
and  girls  living  in  small  rural  communities  or  in  farming 
or  lumbering  sections.  If  you  live  under  such  conditions 
try  to  make  a  score  card  to  fit  your  conditions. 

THOUGHT  QUESTIONS 

1.  Suppose  you  were  visiting  and  were  awakened  in  the  night  by 
the  cry  of  "  Fire  "  and  could  smell  the  smoke.    What  are  some  of 
the  different  conditions  you  ought  to  be  able  to  meet?    Tell  just 
what  you  would  do  under  these  different  conditions. 

2.  How  is  it  that  "  fireproof  "  buildings  are  sometimes  destroyed 
by  fire? 

3.  Prepare  to  debate  one  side  of  this  question.   Resolved :  That  the 
use  of  kerosene  in  the  home  is  a  greater  fire  hazard  than  the  use  of  gas. 

4.  Make  out  a  set  of  rules  needed  in  your  home  to  remove  some 
of  the  present  fire  risk  practices. 

5.  Give  as  many  reasons  as  you  can  why,  considering  all  the  harm 
fire  does,  the  world  is  better  off  with  it  than  it  would  be  without  it.  " 

6.  Plan  a  "  fire  drill "  for  the  home.    Assign  a  particular  thing  for 
each  member  of  the  family  to  do,  as :   giving  the  alarm,  trying  to  ex- 
tinguish the  fire,  saving  things  of  value.     Try  it  out  by  giving  the 
alarm  unexpectedly. 


SCORE  CARD  217 

SCORE  CARD.    FIRE-HAZARD  SURVEY  OF  MY  HOUSE 


SCORE 


Perfect   Allowed 


Fireproof  constructions 
Slate  or  other  fireproof  roof 
Stone,  brick,  or  concrete  walls 


2.  Not  nearer  than  25  ft.  to  other  wooden 

buildings 5 

3.  Metal  ash  cans  used 

Gas  connections  of  metal  pipe,  not  of  rub- 
ber      .       25       _  5 

4.  Matches 

Safety  matches  used 

Out  of  reach  of  children i\  5 

5.  (a)   No  swinging  gas  jets  or  lamp  brackets 

near  curtains. 

Oil  lamps  of  metal,  low,  not  easily 
upset  (5).     Score  either  (a)  or  (b)  .     .  5 

6.  No  one  in  family  is  careless  with  fire 

No  smokers  in  family     ..     .,-....       '2\  5 

7.  No  stove  pipe  through  wall  or  floor       .     .       2 
No  stove  within  one  foot  of  unprotected 

wall 1 1 

Metal  or  asbestos  mat  under  stove  and  ex- 
tending 10  in.  in  front i  \  5 

8.  No  gasoline  kept  in  glass  bottle   .     .' 
No  gasoline  used  for  cleaning  indoors 

Kerosene  never  used  in  kindling  fire      .     .       2  5 

9.  No  rubbish  allowed  to  collect 2 

No  oily  rags  collect  or  left \\ 

No  celluloid  articles  in  house \\  5 

Have  a  hand  fire  extinguisher       ....       2 
Fire  engine  house  within  \  mile    ....       2 
Hydrant  within  300  ft.  of  house  .... 
Fire  alarm  box  within  500  ft.  or  have  a 
telephone       %  5 

TOTAL  : 50 


218  FIRE  PREVENTION  IN  THE  HOME 


REFERENCE  BOOKS 

Adams,    Harper's   Outdoor   Book,    pages    191-200    (Fire   engines).      Harper    and 

Brothers. 
Circular  75.    Safety  for  the  Household,  U.  S.  Bureau  of  Standards :  good  account  of 

fire  hazards  and  treatment  of  injured. 
Croker,  Fighting  Fire.    Dodd,  Mead  and  Company. 
Hill,  Fighting  a  Fire.    The  Century  Company. 
Moffett,  Careers  of  Danger  and  Daring,  pages   200-256  (Life  of    firemen).     The 

Century  Company. 
Report  U.  S.  G.  S.  for  IQOQ:  data  and  comparisons  on  the  amount  of  fire  damage 

done  in  the  U.  S. 

Reports  from  State  Fire  Marshal:  in  most  states. 
Richman  and  Wallach,  Good  Citizenship.     American  Book  Company. 
Safeguarding  the  Home  against  Fire:    A  pamphlet,  91  pp.   By  National  Board  of 

Fire  Underwriters :  very  complete  account  of  causes  of  fires,  how  to  guard 

against  them,  and  what  to  do  in  emergencies. 
Warren,  Stories  from  English  History,  pages  303-307  (Great  fires).      D.  C.  Heath 

and  Company. 

Weeks,  Avoidance  of  Fires.     D.  C.  Heath  and  Company. 
Whitman,  Fire  Hazards  and  Safeguards:  Ten  Lessons.     General  Science  Quarterly. 

March,  1920. 


CHAPTER  XIV 
CLOTHING   AND   ITS   USES 

Problems. — i.    To  understand  How  the  temperature  of 
the  body  is  regulated. 

2.  To  learn  what  is  proper  clothing  for  our  bodies  and 
feet. 

3.  To  see  of  what  our  clothes  are  made. 

4.  How   can   we   detect  fraudulent   materials   in   cloth- 
ing? 

5.  To  see  how  clothing  is  cleaned. 

Experiments.  —  i.   To  distinguish  wool  from  cotton  by  the  burning  test. 

2.  To  show  the  effect  of  chemical  reagents  on  different  fibers. 

3.  Removal  of  spots  and  stains. 

Project  I.  —  To  FIND  OUT  OF  WHAT  MATERIALS  CLOTHES  ARE  MADE. 

1.  Find  out  how  to  make  various,  chemical  tests  for  different 
kinds  of  fibers. 

2.  Find  out  some  of  the   characteristic  physical  properties,  in- 
cluding examination  under  the  microscope  if  possible. 

3.  Practice  in  applying  tests  to  poor  materials. 

4.  Practice  in  applying  tests  to  known  mixtures. 

5.  Use  of  tests  in  determination  of  mked  goods,  or  for  adultera- 
tion, filling,  etc. 

6.  Common  fibers  for  testing:    cotton,  mercerized  cotton,  linen, 
wool,  silk,  artificial  silk. 

7.  Apply  tests  to  determine  composition  of  various   articles  of 
clothing  worn,  if  samples  for  testing  can  be  obtained. 

219 


220 


CLOTHING  AND  ITS  USES 


HAIR. 


8.   Your  report :  Make  diagrams  of  fibers  seen  under  microscope. 
Give  an  account  of  all  testing  work. 
Mount  specimens  of  original  and  tested  cloth. 
Conclusion  regarding  adulteration. 

Suggested  Projects. 

1.  TO   PREPARE   A   TABLE   TO   SHOW   HOW    TO   REMOVE   SPOTS   AND 
STAINS  FROM  DIFFERENT  KINDS  OF  CLOTH. 

2.  TO  MAKE  SOAP  FROM  HOUSEHOLD  GREASE. 

The  skin  regulates  our  body  temperature  .  —  We  are  all 
aware  of  the  fact  that  sometimes  we  feel  hot  or  feel  cold, 

but  if  we  were  to  take 
the  body  temperature  at 
either  of  these  times,  we 
would  find  it  varied  little 
from  its  normal  heat  of 
98.6  degrees.  To  be  sure, 
the  outer  part  of  the 
skin  would  be  colder  on  a 
cold  day  and  warmer  on 
a  warm  day,  but  the  skin 
itself  has  a  very  com- 
plex mechanism  for  regu- 
lating our  body  temperature.  By  means  of  the  sweat 
glands  shown  in  the  diagram  as  little  coiled  tubes,  and  the 
very  delicate  nervous  apparatus  which  we  need  not  now 
try  to  understand,  the  skin  is  enabled  to  regulate  the  heat 
of  the  body.  When  we  do  more  work  and  the  body  be- 
comes warmer  from  the  increased  oxidation  within  it,  the 
skin  automatically  is  enabled  to  throw  off  this  heat  and  it 
is  able  also  to  retain  more  heat  on  a  cold  day. 

How  the  body  loses  heat.  —  Heat  is  lost  from  the  body 
by  the  three  methods  we  have  studied  in  the  preceding 


A  section  through  the  skin. 


HOW  THE  BODY  LOSES  HEAT 


221 


chapters.  A  certain  amount  of  heat  is  lost  by  conduc- 
tion, although  the  air  is  a  very  poor  conductor,  and  warm 
fabrics  get  much  of  their  heat-holding  qualities  because  of 
the  stagnant  air  confined  in  their  meshes.  Most  of  our 
heat  from  the  body  is  lost  by  convection.  When  we 
fan  ourselves,  we  create  a  current  of  air,  causing  cooler  air 
to  replace  the 
warm  air  about 
the  body.  We 
also  lose  heat 
by  radiation  to 
other  solid  ob- 
jects which  are 
cold.  It  is  very 
easy  to  take  cold 
by  sitting  on  the 
damp  ground,  or 


close  to  cold 
windows  or 
walls,  because  in 
this  way  warmth 
is  removed  rap- 
idly from  one 
part  of  the  body. 


Which  side  of  this  boy  will  lose  more  heat  ?     Why  ? 


Curiously  enough,  although  we  feel  warm  when  we  per- 
spire, yet  much  of  the  heat  of  the  body  is  taken  away 
by  evaporation  of  the  water  from  the  body  surface.  On 
a  hot  muggy  day  when  the  atmosphere  about  us  is  moist, 
little  heat  is  lost  by  evaporation  and  we  feel  much  hotter 
than  on  an  equally  hot  dry  day  when  we  perspire  freely. 
A  person  may  feel  the  heat  far  more  in  New  York  on 
a  day  in  August  than  in  the  jungles  of  British  Guiana  at 


222 


CLOTHING  AND  ITS  USES 


the  same  time  of  year,  because  in  the  tropics  the  trade 
winds  cause  rapid  evaporation  of  the  moisture  from  the 
body.  On  a  humid  day  a  blanket  of  stagnant  heated 
air  forms  about  the  body,  which  makes  one  feel  very  un- 
comfortable. For  this  reason  electric  fans  and  the  punkas 
of  India  have  saved  people  from  much  discomfort  by 
keeping  the  air  in  motion,  thus  evaporating  the  moisture, 
and  removing  heat  from  the  body. 

Bathing  and  the  skin.  —  Since  the  skin  is  such  an  im- 
portant organ  for  heat  regulation  and  for  getting  rid  of 
wastes  as  well,  it  goes  without  saying  that  we  should  take 
good  care  of  it.  Bathing  keeps  the  pores  open  and  the 

skin  clean.  In  summer,  when 
perspiration  is  increased, 
baths  should  be  •  more  fre- 
quent than  in  winter.  A  cold 
shower  or  plunge  every  day, 
both  in  winter  and  in  summer, 
is  an  excellent  habit  to  accus- 
tom the  skin  to  different 
changes.  If  you  find  that 
after  a  rubdown  the  skin 
does  not  glow  and  you  feel 
cold  and  chilly,  do  not  take 
the  baths  so  cold.  It  is  al- 
ways well  to  begin  with 
tepid  water  and  gradually  turn  on  colder  as  the  bath  pro- 
gresses. Hot  baths  should  be  taken  only  at  night,  as  they 
tend  to  bring  blood  to  the  skin  and  increase  the  radia- 
tion. When  we  chill  the  body,  the  body  resistance  is 
lowered  and  germs,  which  are  almost  always  present  in  our 
mouths  and  throats,  develop  rapidly  and  cause  a  cold. 


The  blood  is  brought  to  the  surface  of  the 
body  and  there  loses  some  of  its  heat 
through  the  skin. 


HOW  TO  WEAR  CLOTHING 


223 


Underclothes  and  their  uses.  —  In  winter  we  need  under- 
clothes which  are  non-conductors  of  heat,  and  retain  the 
warmth  in  the  body.  In  summer  we  need  underclothes 
that  do  not  hold  moisture,  for  wet,  clammy  underclothes 
cool  us  by  conduction  if  it  is  cold,  or  if  it  is  warm, 
make  us  uncomfortably  hot  by  preventing  evaporation, 
and  sometimes  even  cause  a  cold  to  develop.  It  does 
not  seem  to  make  very  much  difference  what  kind  of 
materials  are  used,  whether 
woolen,  cotton,  linen,  or  silk 
fiber,  so  long  as  the  under- 
clothes are  porous.  Woolen 
underclothes  are  best  for  wear 
in  winter,  because  the  natural 
curly  fiber  makes  them  porous, 
and  also  because  they  absorb 
more  water,  and  this  protects 
the  skin  from  cooling  too  rap- 
idly in  case  we  get  overheated. 
Most  colds  are  taken  because 
people  insist  on  wearing  too 
much  in  winter.  They  wear  heavy  underclothes  and  heavy 
outer  clothes,  then  go  from  a  warm  room  to  the  cold  out- 
doors, and  back  again  to  warm  workrooms  where  the 
temperature  is  often  higher  than  that  of  summer  heat. 
The  better  rule  is  to  wear  a  medium  weight  underwear  in 
winter  and  heavier  outside  clothes,  which  can  be  changed 
as  one  goes  into  different  temperatures. 

How  to  wear  clothing.  —  The  chief  use  for  clothing  is 
to  keep  heat  in  the  body,  although  some  people  think, 
as  in  the  case  of  some  animals  which  wear  their  fur  and 
feathers  for  attraction,  that  "  fine  feathers  make  fine 


Mesh  in  underwear. 


224 


CLOTHING  AND  ITS  USES 


birds."  Heat  does  not  easily  escape  through  dry  air, 
and  clothing  prevents  its  escape  by  holding  air  in  little 
pores  of  the  cloth.  Fur  of  animals,  a  natural  covering, 
is  very  warm,  yet  averages  in  the  case  of  many  animals 
about  98  per  cent  air  and  only  two  per  cent  hair.  The 
outer  clothes,  both  of  boys  and  girls,  should  not  be  very 
tight  fitting,  and  not  too  heavy,  especially  if  heavy  under- 
clothing is  worn.  Tight-fitting  clothes  interfere  with  the 
circulation  of  the  blood  and  are  not  hygienic.  Clothing 
should  therefore  be  loose  and  the  weight  distributed  as 
nearly  equal  as  possible  on  all  parts  of  the  body.  Get  the 
habit  of  wearing  an  overcoat,  and  take  it  off  when  you  go 
into  the  house.  Learn  to  wear  different  weights  of  clothes 
according  to  the  temperature,  keeping  lightweight  and 
more  porous  ones  for  the  hot  weather.  If  you  get  wet, 
do  not  sit  around  in  wet  clothes. 

Care  of  the  feet.  —  It  is  very  important  to  remember 
to  keep  the  feet  dry.      Wet    feet    are  one  of    the   most 

common  causes  of  colds. 

For  ordinary  wear, 
heavy-soled  shoes  may 
keep  the  feet  fairly 
dry,  but  in  case  of  rain, 
it  is  better  to  wear  rub- 
bers, although  most 
people  consider  them 
a  nuisance.  Our  feet 
surely  should  receive 
our  best  care,  for  they  bear  our  body  weight  the  greater  part 
of  the  working  day.  They, are  often  harmed  in  youth  by 
shoes,  especially  in  the  case  of  girls,  who  pride  themselves 
on  the  shapely  appearance  of  the  feet  and  ankles.  The 


A  great  help  in  preventing  a  cold. 


WHERE  OUR  CLOTHES  COME  FROM 


225 


high  heels  worn  by  many  do  much  to  strain  the  muscles 
of  the  feet,  and  are  responsible  for  many  aches  and  pains 
in  later  life,  which  come  as  a  result  of  flat  feet,  broken 
arches,  and  other  ailments.  Corns,  callous  spots,  and 
blisters  are  caused  by  wearing  shoes  of  a  wrong  size  or 
shape  for  the  feet.  Shoes  should  be  long  and  broad  enough 
to  give  plenty  of  room  for  the  toes.  They  should  have  a 


Notice  how  the  high  heel  brings  the  body  support  hi  front  of  the  heel,  causing 
an  unnatural  arching  of  the  bones. 

straight  last,  and  the  heels  should  not  be  too  high.  A 
common  sense  shoe,  sold  by  most  dealers  now-a-days,  is 
better  than  the  longer,  pointed,  high-heeled  shoe  which  is 
fashionable  and  worn  by  girls  who  do  not  realize  the  harm 
caused  by  wearing  a  shoe  which  does  not  fit  the  shape  of 
the  foot. 

Where  do  our  clothes  come  from  ?  —  Most  boys  and  girls 
would  answer  this  question  by  saying  that  their  clothing 
came  from  the  store,  but  if  they  stop  to  think  they  will 
realize  that  animals  have  a  covering  of  either  fur  or  hide 
and  that  man,  too,  uses  these  materials  for  body  covering. 
Long  years  ago  when  primitive  man  lived  on  the  earth, 
he  covered  himself  with  skins  which  were  taken  from  the 
animals  he  killed.  To-day  we  use  these  same  skins,  but 

H.-WHIT.    CIV.   SCI.   IN   THE   HOME — 15 


226 


CLOTHING  AND  ITS  USES 


after  a  process  of  curing  and  softening  they  are  manufac- 
tured into  shoes,  gloves,  and  other  useful  articles.  We 
have  gone  much  further  than  primitive  man  in  the  mak- 
ing of  clothes,  for  we  have  come  to  use  parts  of  plants  as 
well  as  the  wool  and  other  materials  taken  from  animals. 
The  cotton  plant,  linen,  from  flax,  and  other  fibers  such 


Sheep  are  a  great  asset  to  the  wealth  of  our  nation. 

as  jute,  hemp,  ramie,  and  yucca,  as  well  as  that  most 
beautiful  fabric  of  all,  silk,  which  is  taken  from  the 
cocoon  of  the  silkworm,  have  all  been  put  to  man's  best 
uses. 

Wool.  —  Prehistoric  man  domesticated  sheep  because 
he  found  he  could  use  them  for  food  and  the  skins  for 
clothes.  Later  the  wool  was  carded,  spun,  and  woven  by 
hand.  Our  woolen  materials  are  woven  in  factories.  The 


COTTON 


227 


woolen  fibers  vary  from  about  an  inch  to  eight  or  nine 
inches  in  length.  The  long  fibers  are  woven  into  fine 
woolen  cloths,  while  the  short,  coarse  ones  make  some 
kinds  of  worsted  goods.  These  fibers  are  covered  with 


little  projecting 
scales,  which  cause 
them  to  cling  to- 
gether, and  this 
gives  the  cloth  its 
characteristic  woolly 
or  felted  appearance 
and  produces  a  po- 
rous fabric  which,  as 
we  have  seen  before, 
holds  air  and  retains 
heat. 

Cotton.  —  Our 
Southern  states  in 
the  past  produced 
most  of  the  cotton 
used,  but  to-day  cot- 
ton is  grown  in  many 
other  warm  countries,  especially  in  Egypt.  The  cotton 
fiber  is  really  a  product  of  the  flower,  for  as  the  seeds  are 
formed  in  the  pod,  this  fiber  grows  around  them  as  a  pro- 
tection, and  consequently  the  seeds  must  be  removed,. 


Plant  bearing  cotton  ready  to  pick,  showing  the  boll 
or  fruit  containing  seeds  surrounded  by  cotton 
fibers.  (Museum  of  Natural  History.) 


228 


CLOTHING  AND  ITS  USES 


this  being  done  by  a  process  known  as  ginning.  Cotton 
fibers  are  smaller  than  woolen,  and  under  the  microscope, 
have  a  twisted  appearance.  This  twisting  helps  in  the 
manufacture  of  cotton  cloth.  Cotton  fiber  contains  fewer 

air  spaces  than  woolen, 
and  therefore  cotton 
cloth  is  cooler. 

Experiment.  —  To  distinguish 
wool  from  cotton  by  the 
"burning  test." 

Materials:  Cotton  and  wool 
string.  Forceps.  Burner. 

Method:  Set  on  'fire  a  string 
of  cotton  and  one  of  wool 
at  the  same  time. 

Observation  and  Conclusion : 
Which  burns  more 
rapidly?  Which  burns 
with  more  flame?  Ob- 
serve the  odor  from  each. 
Tell  how  to  distinguish 
cotton  from  wool  by  the 
"  burning  test." 

Linen,  —  Flax,  a  little 
plant  with  a  well-known 
blue  flower,  produces  all 
of  our  linen.  The  fiber 
comes  from  the  stems, 
which  have  to  be  rotted 
under  water,  beaten  to 
remove  the  woody  tissue,  spun  and  woven  into  cloth. 
This  industry  formed  a  very  considerable  place  in  the  lives 
of  the  Belgians,  French,  and  Russians  who  lived  in  the  area 
devastated  by  the  World  War.  The  present  high  price 
of  linen  is  due  very  largely  to  the  destruction  by  the 


Flax  grown  for  fiber. 


SILK 


229 


Huns  of  fields  of  flax  and  especially  the  linen  factories  in 
Belgium.  Flax  is  not  an  abundant  plant  in  this  country, 
and  linen  is  harder  to  manufacture  than  cotton ;  hence  it 
is  more  expensive.  Linen  is  stiff,  washes  readily,  and  makes 
up  the  greater  part  of  our  table  linen,  collars,  and  cuffs. 


Silkworm,  cocoons,  chrysalis,  moth,  and  skein  of  silk.     (After  Weed  ) 

Silk.  —  Silk  is  one  of  the  smoothest  and  most  beauti- 
ful cloths  we  have,  as  well  as  a  good  conductor  of  heat. 
The  moth  which  produces  the  silkworm  passes  through 
four  stages,  like  fleas,  mosquitoes,  and  many  other  insects. 
The  eggs  are  laid  by  the  mother  moth  on  the  mulberry 


230 


CLOTHING  AND  ITS  USES 


leaves  which  are  the  food  of  the  little  rapidly  growing 
caterpillars.  They  shed  their  coats  as  they  become 
larger,  but  after  a  time  they  become  quiet,  shrink  a  little 
in  size,  and  spin  a  wonderful  covering  of  silk.  The  silk  is 
made  within  the  body  of  the  caterpillar,  and  is  given  out 


Sorting  the  cocoons  of  the  silkworm,  in  Japan. 

from  just  below  the  mouth,  in  the  form  of  a  jelly-like 
material.  This  hardens  rapidly  into  a  yellow  or  whitish 
thread.  The  process  of  weaving  a  cocoon  takes  from  two 
to  three  days.  The  cocoons  are  gathered,  and  after  plac- 
ing in  hot  water,  the  silk  is  reeled  off,  very  largely  by 
hand.  It  takes  between  two  and  three  thousand  cocoons 
to  make  a  pound  of  silk.  Most  of  the  labor  is  done  by 


DETECTION  OF  FRAUDS 


231 


hand,  hence  silk  making  must   go   on   in   countries   like 
Japan  and  China,  where  wages  are  low. 

Detection  of  frauds  in  clothing.  —  We  all  know  that 
woolen  cloth  frequently  contains  much  cotton.  We  are 
often  sold  mercerized  cotton,  or  artificial  silk,  which  is 
made  by  chemical  means  from  various  vegetable  wastes, 
and  it  is  worth  while  to  know  some  simple  means  for 
detecting  these  frauds.  If  one  has  a  microscope,  it  is 


(a)   Cotton. 


(c)  Silk. 


very  simple  to  recognize  by  examination  the  fiber  of  silk, 
cotton,  linen,  and  woolen  fabrics.  (See  illustration.)  Some 
easy  tests  which  can  be  made  at  home  are  the  following: 
If  we  place  silk  fibers  in  hydrochloric  acid,  they  will  dis- 
solve. By  boiling  wool  in  caustic  soda  for  five  minutes, 
the  wool  dissolves.  Thus  it  is  very  easy  to  find  out 
whether  wool  and  silk  are  mixed  with  other  substances 
in  cloth.  Linen  threads  are  much  stronger  than  cotton. 
A  very  easy  way  to  tell  linen  from  cotton  is  to  place  in 
olive  oil  for  five  minutes ;  if  linen,  the  material  becomes 
translucent;  if  cotton,  it  remains  unchanged. 

Experiment.  —  To  show  the  effect  of  chemical  reagents  on  different  fabrics. 
Materials:  Pieces  of  cotton  cloth,  wool,  and  silk  of  known  purity.     Test 
tubes.     Beakers.     Burner.     Hydrochloric  acid.     Sodium    hydroxide. 
Ammonia.    Borax.    Washing  soda.    Nitric  acid.     Sulphuric  acid. 


232 


CLOTHING  AND  ITS  USES 


Method  and  Results  :  (a)  Shrinking  lest.  Measure  pieces  of  cotton  cloth  and 
woolen  cloth.  Pour  boiling  water  upon  them  and  leave  overnight.  Dry 
without  stretching.  When  dry  measure  again.  Is  there  any  shrinkage  ? 

(&)  Test  the  solubility  of  cotton,  woolen,  and  silk  cloth  in  each  of  the 
following : 

i.  Cold  concentrated  hydrochloric  acid.  2.  Hot  concentrated  hydro- 
chloric acid.  3.  Cold  diluted  hydrochloric  acid.  4.  Hot  diluted  hydro- 
chloric acid.  5.  Make  similar  tests  with  concentrated  and  dilute  nitric 
acid,  and  concentrated  and  dilute  sulphuric  acid,  both  cold  and  hot. 
Also  make  tests  with  cold  and  hot  concentrated  and  dilute  solu- 
tions of  sodium  hydroxide,  ammonia,  borax,  and  washing  soda. 
Note  any  changes  while  the  cloth  is  in  the  solution.  Rinse  and  dry. 
Are  any  other  changes  observed?  Be  very  careful  not  to  get  any  of 
these  solutions  on  your  clothes  or  hands. 

Application:  What  precautions  should  be  taken  in  washing  clothing? 
Can  chemicals  be  used  in  finding  out  how  much  wool  or  other  fiber 
there  is  in  a  certain  piece  of  cloth?  Explain. 

Care  of  the  clothes.  —  Clothes  are  to  be  worn  both  for 
comfort  and  for  looks.     All  girls  like  to  look  attractive, 

but  not  always  so  with  boys. 
How  many  boys  have  lost  a 
good  job  just  because  of  dirty 
collars  and  shirts,  or  carelessly 
blacked  shoes.  We  may  have 
our  clothes  neat  and  clean, 
even  if  they  are  not  new. 
Underclothes  should  be  fre- 
quently changed  and  washed, 
especially  in  hot  weather,  as 
they  absorb  the  perspiration 
and  body  wastes.  We  should 

be  particular   about   changing   socks   and   stockings   fre- 
quently, and  washing  the  feet  often  as  well. 

How  to  clean  clothes.  —  We  know  that  in  order  to  take 
out  soluble  substances  from  clothes  which   have  become 


USE  OF  SOAP  233 

dirty,  we  must  use  plenty  of  soap  and  water.  This  water 
must  be  soft,  because  hard  water  (which  has  certain  min- 
eral substances  dissolved  in  it)  will  not  always  do  its 
work,  even  if  soap  is  used.  It  is  usually  better  to  soak 
the  clothes  in  cold  water  first  to  loosen  the  dirt,  and  later 
to  wash  in  hot  water.  Boiling  water  should  not  be  used 
in  washing  woolen  goods  as  it  renders  them  less  porous 
and  therefore  not  so  warm.  Alkaline  soaps  and  other 
alkalies  should  not  be  used  in  washing  woolens  because 
alkalies  dissolve  wool. 

Bleaching.  —  Sometimes  we  may  bleach  out  the  stains 
after  having  placed  the  clothing  in  the  water,  and  for 
this  purpose,  nature's  own  ways,  sunlight  and  the  oxygen 
of  the  air,  are  useful,  although  bleaching  substances, 
such  as  Javelle  water,  lemon  juice,  cream  of  tartar,  and 
other  substances  are  used.  A  good  home  project  would 
be  to  find  out  the  properties  of  some  of  the  bleaching  agents 
mentioned,  and  some  others  sold  in  stores.  In  Javelle 
water  and  in  most  household  bleaching  agents,  the  substance 
which  does  the  bleaching  is  chlorine,  which  forms  the  base  of 
some  of  the  poison  gases  which  have  done  such  terrible 
havoc  on  the  battle  fields  of  the  World  War.  Chlorine 
or  bleaching  powder  must  not  be  used  in  bleaching  wool  and 
silk  because  it  stains  them  yellow. 

Use  of  soap.  —  We  have  all  heard  of  the  days  when 
our  great-grandmothers  made  soft  soap  by  placing  to- 
gether scraps  of  fat,  butter,  tallow  candles,  and  the  like, 
and  melting  them  down  with  a  strong  solution  of  lye, 
which  was  made  by  treating  wood  ashes  with  lime.  Now 
hard  soap  is  made  by  the  addition  of  certain  other  sub- 
stances and  it  has  become  a  necessity  of  our  lives.  Soap  is 
a  solvent  which  breaks  grease  up  into  tiny  particles,  form- 


234  CLOTHING  AND  ITS  USES 

ing  an  emulsion,  and  in  this  condition  it  is  carried  off  in 
the  water  from  our  hands  and  substances  on  which  it  is 
placed.  The  Germans  during  the  late 
war  suffered  greatly  from  the  lack  of 
soap. 

Washing  powders  and  their  use.  - 
When  water  is  hard  or  contains  mineral 
substances,  such  as  lime  or  magnesium, 
soap  cannot  well  be  used.     It  is  less 

An    emulsion  seen    under     Wasteful  of  SOap  if  SUch  Waters  are  first 
the  microscope.  .    . 

softened  by  the  addition  of  washing 
powders.  These  usually  have  washing  soda  as  a  base,  which 
combines  chemically  with  the  lime  in  the  water,  changing  it 
to  an  insoluble  form,  so  that  it  does  not  affect  the  soap. 
Washing  powders  should  be  dissolved  in  a  tub  of  water 
before  the  clothes  are  put  in. 

Neutralization.  —  Dirt  and  some  stains  are  removed 
from  materials,  as  we  have  seen,  by  solution  and  by 
bleaching.  Other  stains  can  be  removed  by  a  process 
known  as  neutralization.  Vinegar  and  many  fruit  juices 
have  a  sour  taste  and  will  turn  a  piece  of  blue  litmus 
paper  red.  A  similar  color  change  occurs  when  blue 
litmus  paper  is  placed  in  the  presence  of  any  diluted  acid, 
such  as  nitric  or  sulphuric.  This  is  a  test  for  acids.  Other 
substances  which  have  a  bitter  taste  and  a  soapy  feeling 
are  called  bases.  Lye  in  soap  is  a  strong  base,  as  is  soda, 
also.  We  find  that  if  bases  are  tested  with  red  litmus 
paper,  it  turns  blue.  We  therefore  have  an  artificial  test 
for  acids  and  bases.  If  we  now  add  to  a  solution  con- 
taining a  base  some  acid  drop  by  drop,  and  keep  testing 
with  red  litmus  paper,  we  find  at  length  that  the  com- 
bination of  acid  and  base  does  not  affect  the  paper.  Neither 


REMOVAL  OF  GREASE  235 

red  litmus  paper  turns  blue,  nor  blue  paper  red,  in  the 
presence  of  this  combination.  Such  a  mixture  as  this  is 
said  to  be  neutral.  In  cleaning  we  make  use  of  neutral- 
ization, by  using  acids  to  remove  stains  caused  by  bases, 
and  by  using  bases  to  remove  stains  caused  by  acids. 

Experiment.  —  Removal  of  spots  and  stains. 

Materials:  Strips  of  white  cotton  cloth.  Congo  red  solution.  Sodium 
carbonate.  Lemon.  Ammonia.  Acetic  acid  or  white  vinegar. 
Salad  oil.  Lard.  Butter.  Alcohol.  Gasoline.  Carbon  tetrachlo- 
ride.  Oxalic  acid.  Black  ink.  Red  ink.  Test  tubes. 

Adds  and  alkalies:  Dye  one  strip  of  white  cloth  in  Congo  red.  A  sec- 
ond in  Congo  red  to*  which  is  added  a  pinch  of  sodium  carbonate. 
Dry  them.  What  are  the  colors? 

Let  a  drop  of  lemon  juice  (an  acid)  fall  on  the  blue  cloth.  Result. 
Try  to  restore  the  color  with  ammonia.  Let  a  drop  of  ammonia  fall 
on  the  red  cloth.  Result.  Try  to  restore  the  color  with  acetic  acid 
or  vinegar. 

Acids  and  alkalies  have  opposite  properties  and  each  tends  to 
destroy  the  other. 

Grease  spots:  Dirt  held  by  oil  or  grease  can  only  be  removed  by  the 
removal  of  the  oil  or  grease.  Test  the  solubility  of  salad  oil,  lard, 
and  butter  in  water,  alcohol,  gasoline,  carbon  tetrachloride.  Results? 
Suggest  a  good  way  to  remove  grease  spots  from  clothing.  What 
danger  is  there  in  using  gasoline? 

Fruit  and  ink  stains :  Try  cold  water,  then  hot  water.  Oxalic  acid  will 
remove  black  ink  containing  iron.  White  cotton  or  linen  may  be 
treated  with  Javelle  water.  The  cloth  must  be  thoroughly  washed 
in  dilute  ammonia  afterwards. 

NOTE  :  Use  alcohol  for  grass  stains ;  dilute  hydrochloric  acid  for 

.  rust ;  turpentine  for  paint ;  benzole  for  tar,  and  sulphurous  acid  or 
hydrogen  peroxide  for  bleaching  white  woolens,  silks,  and  linens. 

Removal  of  grease.  —  An  easy  way  to  remove  grease 
from  clothing  is  to  cover  the  grease  spot  with  blotting 
paper  and  press  with  a  hot  iron.  The  grease  is  melted 
by  the  heat  and  absorbed  by  the  blotter,  which  draws  the 
liquid  up  into  it  by  capillary  attraction.  Grease  and  oils 


236  CLOTHING  AND  ITS  USES 

may  also  be  absorbed  by  French  chalk,  or  a  mixture  oi 
starch  and  gasoline.  Tar  can  often  be  removed  by  cov- 
ering the  substance  first  with  lard,  then  heating  this  for 
some  time  and  washing. 

An  interesting  home  project  would  be  to  make  a  series 
of  experiments  to  determine  what  methods  were  best 
fitted  to  remove  different  stains  from  clothes.  Why  not 
try  this? 

Use  of  the  score  card.  —  This  is  a  very  important  per- 
sonal card  and  should  be  scored  with  great  care.  Your 
total  score  only  need  be  given  in  class  or  in  your  notebook. 
Try  to  improve  at  once  in  matters  where  your  score  is 
low.  In  some  of  the  personal  matters  you  surely  can  do 
this.  Score  again  in  a  month  to  see  how  much  you  have 
improved. 

REFERENCE   BOOKS 

Allen,  Asia  (Chapters  on  Silk  Production).     Ginn  and  Company. 

Allen,  Europe  (Chapters  on  Flax  and  Silk).     Ginn  and  Company. 

Bassett,  The  Story  of  Wool.     Perm  Publishing  Company. 

Brownell,  General  Science,  Chapter  IX.     P.  Blakiston's  Son  and  Company. 

Buchanan,  Great  Inventors  and  Their  Inventions  (Eli  Whitney  and  the  Cotton  Gin). 
American  Book  Company. 

Carpenter,  How  the  World  is  Clothed.     American  Book  Company. 

Clark,  An  Introduction  to  Science,  Chapters  XI,  XV.     American  Book  Company. 

From  Wool  to  Cloth.     American  Woolen  Company,  Boston.     (Free) 

Fall,  Science  for  Beginners,  Chapter  XIII.     World  Book  Company. 

Gannett,  Commercial  Geography.     American  Book  Company. 

Hunter,  A  Civic  Biology,  Chapters  X,  XV.     American  Book  Company. 

Sargent,  Plants  and  Their  Uses.     Henry  Holt  and  Company. 

Bddmer,  The  Book  of  Wonders  (Story  of  Cotton,  Wool,  and  Silk).  Presbrey  Syn- 
dicate, N.  Y. 

Toothaker,  Commercial  Raw  Materials.     Ginn  and  Company. 

Turner,  The  Study  of  Fabrics.     Appleton  and  Company. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  XIV.  Houghton 
Mifflin  Company. 

Weed,  Chemistry  in  the  Home.    American  Book  Company. 


SCORE  CARD 


237 


SCORE  CARD.    CLOTHING,  BATHING,  VENTILATION 


SCORE 

PER- 

MY  i 

SCORE 

SCORE 

Total 

Outer  clothes 
Clothes 
fit  well  but  loosely  worn      
sensible  in  color  and  pattern    
well  washed  and  mended 

2 
2 
2 



Collar  and  shoes  clean  .... 

2 

Shoes  sensible  width  and  style     

2 

Underclothes 
Mesh  underwear  worn        .... 

2 

Woolen  underwear  in  winter  ....          . 

2 

Socks  and  stockings  changed  every  other  day    . 
Underclothes  changed  every  other  day  in  sum- 
mer, oftener  if  odor  is  noticeable     .... 
Wear  warmer  outer  clothes  in  winter  or  on  going 
out  of  doors  in  cold  weather    

2 
2 
2 

Bathing 
Tub  bath  weekly  :  twice  a  week  in  summer 
Feet  bathed  every  other  day 

2 
2 

Shower  or  cold  rub  in  morning    . 

2 

Face,  neck,  and  ears  washed  with  soap  and  water 
every  morning 

2 

Hands  washed  before  and  after  meals  and  after 
going  to  toilet    '   « 

2 

Bedroom  hygiene 
Window  space  equal  to  \  floor  area      .     ... 
Windows  screened  full  length      ...... 
Windows  open  top  and  bottom  at  night  or  sleep- 
ing porch       

2 
2 

- 

No  hangings 

j 

No  draft  on  bed    . 

I 

Home  ventilation 
Ventilation  in  every  room  in  house      .     ... 
Air  seldom  seems  "  close  "  or  "  stuffy  "      .     .     . 
Sunlight  not  kept  out  by  heavy  curtains  .     . 
House  aired  thoroughly  once  a  day      .... 
Drafts  avoided      .     , 

2 
2 
2 
2 
2 

TOTAL   

CQ 

PART    IV.     LIGHT    IN   THE    HOME 

CHAPTER  XV 
SOURCES    OF   LIGHT   FOR   HOME    USE 

Problems.  —  i .    To  understand  the  importance  of  light 
and  eyes. 

2.  To  see  what  important  properties  of  light  we  utilize. 

3.  To  understand  how  my  home  is  lighted  by  natural  means. 

4.  To  understand  how  my  home  is  lighted  by  artificial 
means. 

5.  To  compare  the  different  types  of  lighting. 

Experiments    and    demonstrations.  —  i.   To    show    degrees    of  trans- 
parency. 

2.  To  show  the  advantage  of  the  mantle  in  gas  lighting. 

3.  To  show  how  electricity  may  be  changed  into  light. 

4.  To  show  the  advantage  of  tungsten  over  carbon  lamps. 

Project  I.  —  To  IMPROVE  THE  LIGHTING  OF  MY  HOME. 

1.  Take  up  question  of  quantity  of  light,  natural  and  artificial, 
for  various  kinds  of  work,  and  whether  other  devices  would  cut 
down  expense  of  artificial  light. 

2.  If  some  room  is  poorly  lighted  in  daytime,  can  you  devise  a 
remedy  ? 

3.  What  about  shades,  glare,  and  harmful  habits  in  the  use  of 
light? 

4.  Have  you  a  satisfactory  switch  or  button  installation  for  turn- 
ing lights  on  and  off?     Additional  lamps  needed  anywhere? 

238 


HOW  DOES  THE  SKY  GIVE  LIGHT?  239 

Suggested  Projects. 

1.  MAKE  A  TOY  PERISCOPE. 

2.  TO   USE   A   LARGE    GLASS   AS    A   MIRROR  FOR   "  STAGE    TRICKS." 

See  Book  of  Magic,  HOPKINS. 

Light  and  mankind.  —  Have  you  ever,  while  looking 
out  of  the  window,  put  your  hands  over  both  eyes,  and 
then  tried  to  imagine  what  life  would  be  without  light? 
What  a  dismal  place  the  earth  would  be !  We  have  come 
to  depend  very 
much  upon  the  sun 
and  its  radiant  en- 
ergy, which  travels 
to  us  across  an 
ether  space  just  as 
heat  does,  and  our 

homes      have      been  The  sun  is  the  source  of  all  energy. 

planned  so  that  we  can  make  use  of  all  sources  of  light, 
both  natural  and  artificial.  Much  of  our  light  comes 
from  the  sky  rather  than  directly  from  the  sun.  The  area 
of  the  sky  visible  from  our  windows  is  very  important, 
because  it  is  from  this  that  we  get  most  of  our  light.  The 
sun  at  midday  is  so  bright  we  can  look  at  it  only  with 
strongly  smoked  glasses,  and  we  all  enjoy  the  long  twilight 
of  summer  following  the  light  of  day,  when  no  sun  is 
visible. 

How  does  the  sky  give  light  ?  —  This  seems  a  simple 
question,  but  in  order  to  understand  how  light  comes  to 
us,  we  must  first  learn  some  very  important  properties  of 
light.  If  we  place  a  lighted  candle  or  lamp  on  the  table, 
we  can  all  see  it.  If  we  hold  a  piece  of  window  glass  in 
front  of  it,  the  glass  does  not  in  any  way  obstruct  the  light. 
We  call  such  an  object  transparent.  On  the  other  hand, 


240 


LIGHT  IN  THE  HOME 


a  piece  of  oiled  paper  or  ground  glass,  if  placed  in  front  of 
the  candle,  allows  a  certain  amount  of  light  to  go  through, 
but  we  cannot  see  the  flame  distinctly.  Such  a  sub- 
stance is  called  a  translucent 
body.  If  we  now  take  a  board 
or  piece-  of  sheet  metal  and  hold 
it  before  the  light,  it  prevents 
any  light  from  reaching  our  eyes. 
Such  a  substance  is  called  an 
opaque  body,  and  behind  such  a 
body,  the  space  from  which  light 
is  excluded  is  called  a  shadow. 
Light  passes  through  transparent 
bodies  without  much  loss  or 
scattering  of  the  rays.  Less 
light  passes  through  translucent 
bodies,  and  there  is  much  scat- 
tering of  the  rays  of  light,  while 
no  light  at  all  passes  through 
opaque  bodies. 


Which  obstructs    the    most  light? 
Which  the  least  ? 


Experiment.  —  Transparency. 

Hold  glass,  oiled  paper  or  ground  glass,  and  sheet  metal  in  turn  between 
your  eyes  and  a  light.     Explain  the  different  effects. 

Reflection  and  its  reasons.  —  If  you  take  a  smooth 
surface,  such  as  a  mirror,  and  allow  light  to  fall  on  it,  a 
strong  beam  is  reflected,  while  from  a  roughened  surface 
no  such  beam  passes,  the  light  being  scattered  from  the 
irregular  surface,  or  diffused.  It  has  long  been  known 
that  light  striking  a  flat  smpoth  surface  would  be  reflected 
from  it  at  exactly  the  angle  at  which  it  strikes  it.  If, 
in  a  beam  of  sunlight  the  rays  which  travel  parallel  to  each 


NATURAL  LIGHT  IN  THE  HOME  241 

other  strike  a  roughened  surface,  they  are  thrown  off  in 
different  directions  and  produce  diffused  light. 

Light  from  the  sky.  —  We  are  now  better  able  to  under- 
stand why  we  get  light  from  the  sky.  The  air  always 
contains  particles  of  solid  and  liquid  material,  as  dust, 
and  moisture.  It  is  very  seldom  that  the  air  is  clean,  and 
then  only  at  points  far  above  the  earth,  and  even  in  this 
air  there  are  enough  of  these  dust  particles  to  divert  the 


Which  surface  diffuses  light  ? 

rays  of  light  from  the  sun.  Since  the  surfaces  of  these 
particles  are  irregular,  the  light  is  diffused  in  all  direc- 
tions. Thus  it  is  that  particles  in  the  air  above  our  homes, 
receiving  sunlight,  divert  some  of  these  rays  to  us,  no 
matter  where  we  may  be  situated.  If  there  were  neither 
air  nor  any  other  substance  about  the  earth,  then  the  sky 
would  appear  dark,  and  we  would  only  get  light  directly 
from  the  sun,  the  moon,  and  other  bodies  in  the  heavens, 
the  stars  and  the  planets. 

Natural  light  in  the  home.  —  Fortunate  is  the  boy  or 
girl  who  lives  in  a  detached  house,  for  direct  sunlight 
bathes  the  house  on  bright  days,  and  some  of  it  is  sure  to 
enter.  Within  the  crowded  city  with  its  tall  buildings 
standing  close  together,  with  one  home  piled  on  top  of 
another,  as  we  have  in  apartments,  people  are  fortunate 
if  they  get  direct  light  in  more  than  one  or  two  rooms,  and 

H.-WHIT.   CIV.  SCI.   IN  THE  HOME  —  1 6 


242  LIGHT  IN  THE  HOME 

in  many  city  homes  no  direct  light  enters  at  all.  Light 
is  of  much  importance  to  us,  not  only  because  we  see  ob- 
jects by  the  light  which  comes  from  them,  but  also  be- 
cause it  benefits  health,  and  destroys  bacteria.  We  must 
also  remember,  if  we  live  in  the  country,  that  too  much 
shade  and  too  many  trees  are  as  bad  as  too  few.  Trees, 


A  house  with  plenty  of  light. 

hills;  and  buildings,  as  well  as  porches  and  other  overhang- 
ing parts  of  the  house,  all  cut  off  light  from  our  houses. 

Regulation  of  sunlight  in  the  home.  —  It  is  a  very  good 
rule  in  planning  a  house  to  have  the  window  space  of  a 
room  one  fourth  to  one  fifth  of  its  floor  space.  This  will 
give  a  sufficient  amount  of  light  for  most  purposes.  The 
bedroom  may  have  less  window  space,  but  no  bedroom 
should  ever  shut  out  light  and  air  by  having  window  hang- 
ings and  draperies.  If  the  wall  paper  and  woodwork 
of  the  room  are  dark,  the  room  itself  will  be  dark,  for  dark 
objects  absorb  light.  As  a  rule  the  ceiling  should  be 
lightest,  the  walls  a  little  darker,  and  the  floor  still  darker. 


ARTIFICIAL  LIGHT  IN  OUR  HOMES 


243 


This  gives  good  distribution  of  light  within  the  room.  If  a 
room  is  too  light,  and  at  the  same  time  too  hot  in  summer, 
we  can  adjust  the  amount  of  light  entering  by  means  of 
blinds  or  awnings.  The  Venetian  blind  or  porch  shade  is 
a  convenient  type  to 
use,  for  it  shuts  out 
the  sun's  rays  with- 
out preventing  a  cir- 
culation of  air. 

Artificial  light  in 
our  homes.  —  It  was 
not  so  many  years 
ago  that  candles 
were  the  sole  source 
of  light  in  our  homes, 
and  at  the  present 
time,  candle  light 

lends  a  pleasant  glow  to  birthday  and  Christmas  parties. 
Up  to  the  time  of  the  Civil  War,  tallow  candles,  pine  knots, 
and  heavy  oils  were  common  sources  of  light  for  reading. 
People  to-day  use  eighteen  times  as  much  light  as  they 
did  one  hundred  fifty  years  ago,  and  at  one  third  the  cost. 

The  first  gas  plant  in  America  was  started  at  Philadelphia 
in  1815.  Then  candles  cost  two  and  one-half  cents  each 
and  would  burn  for  seven  hours.  About  the  middle  of  the 
nineteenth  century  the  whaling  industry  was  at  its  height, 
and  sperm  oil  was  burned  in  lamps.  Petroleum  was  first 
used  in  1858  for  lighting  purposes,  and  so  rapidly  did  its 
use  grow  that  in  1860,  two  million  barrels  were  produced, 
and  to-day,  almost  three  hundred  million  barrels  a  year. 
Although  artificial  gas  was  slow  in  its  introduction,  yet 
it  now  plays  a  very  important  part  in  the  lighting  of  our 


Both  these  rooms  receive  the  same  amount  of  light. 
One  has  dark  wall   paper  and   the   other   light. 


244 


LIGHT  IN  THE   HOME 


houses.  About  1890,  electricity  began  to  come  into  general 
use  for  lighting  purposes,  and  is  now  one  of  our  best  known 
servants  in  the  home. 

Kerosene   light.  —  Kerosene  oil  lighting  is  still  one  of 
the  common  methods  of  illumination,  especially  in  country 

homes.  When  oil  first  came 
into  use,  it  burned  with  a 
smoky  flame,  until  in  1783, 
Argand,  a  Swiss  physician, 
made  a  ring-shaped  wick  with 
a  central  draft.  This  allowed 
convection  currents  to  be  set 
up  inside  the  wick,  and  thus 
a  larger  flame  could  be  fed 
with  oxygen.  Flat  wick  lamps 
which  give  smokeless  flames 
are  now  in  common  use,  but 
the  central  draft  lamp  gives 
more  light.  The  gasoline 
lamp  and  acetylene  lamp, 
although  used  in  many  places, 
are  not  in  sufficiently  com- 
mon use  to  warrant  a  full 
description  here. 
Gas  in  the  home.  —  Although  not  all  of  us  are  fortunate 
enough  to  have  either  natural  or  artificial  gas  in  the  home, 
yet  we  should  know  something  about  the  gas  burner  and 
its  uses.  When  a  candle  burns,  as  we  know,  the  paraffin 
wax  melts,  becomes  a  vapor,  and  burns.  You  can  prove 
that  the  gas  inside  of  the  candle  flame  is  not  on  fire  by 
passing  a  small  tube  into  it,  leading  out  the  gas,  and  then 
lighting  it.  When  gas,  passing  from  the  outlet  of  an  ordi- 


AlR 


Central-draft  oil  lamp. 


GAS  IN  THE  HOME 


245 


nary  burner,   has  not  been   previously   mixed  with  air, 

a  yellow  flame  results.     This  is  a  very  wasteful  type  of 

burner.     The  Bunsen  burner,  in  which 

air  is  mixed  with  the  gas,  gives  a  clean 

hot  flame  which  is  not  very  luminous. 

A  combination  of  this  type  of  burner, 

which    produces    much    heat,    with    a 

mantle  which  glows  when  heated,  gives  us 

the  Welsbach  light.    .Welsbach  mantles 

are  made  from  compounds  of  two  rare 

metals,  thorium  and  cerium,  which  when 

heated  to  a  high  temperature  give  the 

bright  light  we  are  so  familiar  with. 


—  Am, 


A  Bunsen  burner. 


Experiment.  —  To  show  the  advantage  of  the  mantle  in  gas  lighting. 

Connect  a  common  fishtail  burner  and  a  Thorp  gauge  to  the  gas  supply. 
Light  the  burner  and  see  how  many  cubic  feet  of  gas  per  hour  are 


Effect  of  gas  appliance  on  cost  of  gas.    Black  =  minimum ;  Black  and  white  =-•  maximum ; 
M  =  mean  cost  per  hour. 


246 


LIGHT  IN  THE  HOME 


registered.     Replacing  the  fishtail  burner  by  a  mantle  and  burner, 
how  does  the  light  produced  in  the  two  cases  compare?     How  much 
gas  is  being  consumed  in  the  latter  case  ?     What  is  your  conclusion  ? 
(If  a  Thorp  gauge  is  not  available,  test  the  gas  consumed  in  a  specified 
time  by  observing  the  small  indicator  of  the  gas  meter  dial.) 

The  first  electric  lamp.  —  It  is  due  Jto  Thomas  Edison 
that  we  have  the  incandescent  light.  The  story  of  its 
invention  is  well  known.  He  worked  for  a  great  many 
years  and  spent  hundreds  of  thousands  of  dollars  in  the 

perfection  of  the  bulb  light, 
patented  in  1880,  which  he 
furnished  finally  with  a  car- 
bon filament,  made  of  bam- 
boo. The  way  in  which 
this  filament  gives  light  can 
be  explained  better  after  we 
have  performed  an  experi- 
ment to  illustrate  what 
makes  electricity  give  light. 
Electricity  is  a  form  of 
energy  which  is  conducted 
easily  by  metals.  We  have 
all  seen  that  the  pipe  con- 
ducting liquids  in  the  house  offers  resistance  to  them  so  that 
they  do  not  flow  so  easily.  In  somewhat  the  same  way 
wires  offer  resistance  to  electricity.  That  part  of  the  elec- 
trical energy  used  in  overcoming  this  resistance  to  the  wire 
conductor  is  changed  into  heat,  which  when  intense  enough 
produces  light.  This  may  be  shown  by  the  following  ex- 
periment : 

Experiment.  —  To  show  how  electricity  may  be  changed  into  light.     (To  be 
performed  by  the  teacher.) 


The  carbon  filament  incandescent  lamp  and 
the  modern  tungsten  lamp. 


THE  FIRST  ELECTRIC  LAMP 


247 


Suspend  a  ten-foot  length  of  fine  iron  wire  (No.  26)  from  insulated 
supports.  Fasten  one  wire  of  a  no- volt  circuit  to  one  end  of  the 
iron  wire,  and  bring  the  other  end  of  this  circuit  in  contact  with  the 
other  end  of  the  wire.  Move  the  end  of  the  circuit  wire  along,  shorten- 
ing the  length  of  the  iron  wire  until  it  becomes  red  hot.  All  this  heat 
energy  is  produced  at  the  expense  of  electrical  energy.  As  the  wire  is 
shortened  the  heat  increases.  The  hotter  the  wire,  the  greater  per  cent 
of  electrical  energy  is  changed  to  heat. 


COST  OF  ELECTRIC  LIGHT 


4O  Woctt    rToryla  -D  Lamp  1907  - 1913 
1000  Woctt  ITajdUx- C  Lamp  1914- -1920 


Graph  showing  decrease  in  cost  of  electric  lighting  in  forty  years.  A  is  the  reduction 
due  to  lamp  improvement  only ;  B,  due  to  lamp  improvement  and  reduced  rates 
for  current. 

We  thus  see  from  the  result  of  tbis  experiment  that  it  is 
more  economical  to  use  electric  bulbs  which  contain  fila- 
ments which  can  be  raised  to  high  temperatures.  Why? 


Experiment.  —  To   show  the   advantage   of  tungsten  over  carbon  lamps. 

Connect  one  or  more  small  carbon  lamps  in  a  circuit  with  a  kilowatt- 
hour  meter.  Find  the  electrical  energy  used  in  running  these  lamps 
for  a  definite  time,  say  one  hour.  Replace  the  lamps  by  an  equal 
number  of  small  tungsten  lamps  (25  watt),  and  find  the  electrical 
energy  consumed  during  an  equal  interval  of  time. 

Each  carbon  lamp  gives  16  candle  power,  and  each  tungsten  lamp  gives 
20  candle  power.  Reckoned  on  the  basis  of  candle  power,  what  is 
the  ratio  of  cost  of  running  the  two  types  of  lamps  ? 


248 


LIGHT  IN   THE   HOME 


The    tungsten    light.  -  -  The    old    carbon    filament    is 
rapidly    being    replaced    by    the    tungsten    lamp.      The 

carbon  filament  can 
be  heated  to  1850 
degrees  Centigrade, 
while  the  tungsten 
filament  can  be 
heated  to  2100  de- 
grees Centigrade,  and 
in  bulbs  which  are 
filled  with  nitrogen, 
the  temperature  may 
go  still  higher ;  there- 
fore we  get  a  much 
brighter  light  from 
the  tungsten  lamp. 
A  one  hundred  candle 
power  tungsten,  ni- 
trogen-filled bulb  re- 
quires only  about  one 
seventh  as  much  elec- 
tricity as  the  one 
hundred  candle 
power  carbon  lamp. 
The  table  on  the  fol- 


GAS OPSN 


GAS 


CARBON  ELECTRIC 


Cost, 


EUCTR1C 

5       10       15      20 
1000  CctTXoLle, 


30       35 
IT\ 


This  chart,  suggested  by  the  Bureau  of  Standards, 
shows  the  relative  cost  of  light  from  different  illu- 
minants,  based  on  the  following  prices :   candles, 
i2fi  a  pound;  kerosene,  15  i  a.  gallon;  gas,  $i  per 
1000  cu.  ft.;    electricity,   io*i  per  kilowatt-hour. 
Solid  black  represents  cost  of  fuel,  and  shaded,      lowinP"      naP"P      show«i 
cost  of  mantles  and  bulbs.     Revise  this  chart  in       IUW1I15      Pd5e 
your  notebook  to  agree  with  cost  of  these  illumi-      some     common    liffht 
nants  in  your  own  city    or    town.  null    iigiit 

intensities.    A   good 

home  project  would  be  to  find  out  the  difference  in  the 
cost  of  lighting  your  home  with  the  fishtail  gas  flame,  the 
Welsbach  gas  flame,  carbon  filament  electric  lights,  and 
tungsten  filament  lights. 


METHODS  OF  LIGHTING 


249 


TABLE  OF  INTENSITIES  OF  COMMON  TYPES  OF  LIGHTING 


The  common  carbon  incandescent  lamp 

The  small  tungsten  incandescent  lamp 

The  fishtail  gas  flame 

The  Welsbach  gas  flame 

A  zoo-watt  tungsten  incandescent 


1 6  candle  power 
20      "          " 

22         "  " 

60    "       " 

Q2         " 


// / ;  i  •  \  \  \ 
'  /  / ;  I  I '  \  '1 


'  /  I    \    \      V    ' 

x  /T*»M» 


Explain  how  these  pictures  illustrate  direct,  indirect,  and  semi-indirect  lighting. 

Methods  of  lighting.  —  Several  ways  of  lighting  by  elec- 
tricity are  now  in  use.  In  direct  lighting,  the  light  is  thrown 
directly  from  the  lamp  or  by  a  reflector  to  the  place  where 
it  is  used.  This  produces  a  glare  in  some  directions  and 
has  some  disadvantages  which  we  shall  study  in  connec- 
tion with  the  eye.  Direct  lighting  is  economical  because 
little  light  is  lost  through  diffusion  or  absorption. 


250 


LIGHT  IN   THE   HOME 


In  indirect  lighting,  an  opaque  reflector  comes  between 
the  eye  and  the  bulb  and  all  light  is  directed  upward  to  a 
white  or  light  colored  ceiling.  Here  the  light  is  diffused, 
and  this  resembles  daylight  in  its  general  effect.  It  is  not 
economical,  but  is  pleasant  and  restful  for  the  eyes.  In  semi- 
indirect  lighting,  a  translucent  reflector  throws  most  of  the 
light  to  the  ceiling.  Some  light  passes  through  the  shade. 
There  is  no  glare  in  this  system,  and  its  cost  is  interme- 
diate between  the  other  two  systems. 

Use  of  the  score  card.  —  Here  the  boy  and  girl  in  the 
country  will  probably  have  the  advantage  in  natural  light- 
ing, but  the  city  child  will  perhaps  have  better  conven- 
iences in  artificial  light.  Study  carefully  to  find  out  the 
relative  cost  of  your  lighting  system  and  make  inquiries 
as  to  the  cost  of  light  in  your  town,  if  you  have  gas  or 
electricity.  What  improvement  in  your  home  lighting  can 
you  suggest? 


SCORE  CARD.    LIGHTING  MY  HOME 


MY  SCORE 

Total 

SUNLIGHT 

Three  fourths  of  all 

Half    rooms    have 

No  rooms  have  di- 

rooms   have    di- 

direct     sunlight 

rect  sunlight   (o) 

rect  sunlight   (4) 
All      rooms      well 

(2) 
Half     rooms     well 

No  rooms  in  which 



lighted  by  natural 

lighted  by  natu- 

artificial  light  is 

light.       No  arti- 

ral light;  no  arti- 

not needed  before 

ficial  light  needed 

ficial  light  needed 

sundown  (o) 

until    after   sun- 

until   after    sun- 

down (2) 

down  (i) 

Home  not  directly 

House  partly  shaded 

House  d  ensely 

shaded   by   trees 

(i) 

shaded  (o) 

or    other    build- 

ings (2) 

Well-lighted      airy 

Cellar  not  light  but 

Cellar     dark     and 

cellar  (2) 

airy  (i) 

musty  (o) 

WINDOWS 

Window    space    at 

Window,  space    at 

Window  space  less 

AND 
WALL 

least  £  floor  space 
(av.    all    rooms) 

least  1  floor  space 
(2) 

than  £  floor  space 
(o) 

PAPER 

(4) 

USE  OF  THE  SCORE  CARD 


251 


SCORE  CARD.    LIGHTING  MY  HOME  —  Continued 


MY  SCORE 

Total 

WINDOWS 
AND  WALL 

Awnings  or  shutters 
provided  (2) 

Shutters,    no   awn- 
ings (i) 

No  shutters  or  awn- 
ings (o) 

PAPER 

No   dark   hangings 
at  windows  (2) 

Dark    hangings    at 
some  windows  (i) 

Dark    hangings    at 
most  windows  (o) 

No    rooms    having 

One      half      rooms 

Three  fourths 

dark  wall  papers 

having  dark   pa- 

rooms        having 

(2) 

pers  (i) 

dark  wall   paper 

(o) 

COST 

Economical 

Moderately       eco- 

Expensive (o) 

OF 

(Consult    tables, 

nomical  (5) 

ARTIFICIAL 

page     245,    and 

LIGHTING 

diagram,       page 

248)  (10) 

PROPER 

Light  used  gives  no 

Sometimes      direct 

Usually  direct  light 

LIGHTING 

glare    and     does 

light  in  eyes   (i) 

in  eyes  (o) 

FOR   ALL 

not  shine  in  eyes 

KINDS   OF 

when  reading  or 

WORK 

at    dining    table 

(2) 

Strong     light     for 

Fair  light  for  sewing 

Poor  light  for  sew- 

sewing (2) 
Kitchen  well  lighted 

•  d) 
Good  light  at  sink 

ing  (o) 
Poor  light  all  parts 

(2) 

or  range,  not  at 

of  kitchen  (o) 

both  (i) 

Lights  both  sides  of 
mirror   in    bath- 

Light  on   one   side 
bath  mirror  (i) 

No  light  near  bath- 
room mirror  (o) 

room  (2) 

No       carrying       of 

Necessary  to  carry 

Always  necessary  to 

lights    from    one 

light      to      some 

carry  light  from 

part  of  the  house 

parts  of  the  house 

one  room  to  an- 

to another  (2) 

d) 

other  or  to  light 

with  matches  (o) 

CON- 

Gas     or      electric 

Gas  or  electric  con- 

Oil lamps  used  (o) 

VENIENCE 

wall  switches  (2) 

trol    at     jet     or 

OF 

socket  (i) 

LIGHTING 

Switch  on  one  floor 

Switch    control    of 

No   switch   control 

SYSTEM 

turns  on  light  on 

light  upstairs  and 

from        different 

other  floors  (2) 

down  but  not  to 

floors  (o) 

cellar  (i) 

Either  floor  sockets 

Some,  but    insuffi- 

No   extra    connec- 

for  electric  con- 

cient extra   con- 

tions (o) 

.... 

nection  or  extra 

nections  (i) 

gas      connection 

for  small   heater 

or  gas  iron  (2) 

Different    amounts 

Variation    of    light 

Variation    of    light 

of  light  easily  ob- 

intensity possible 

difficult    in    any 

tained    in    most 

in    only    a     few 

room  (o) 

rooms  (2) 

rooms  (i) 

Lighting        service 
never  interrupted 

Service  occasionally 
interrupted  (i) 

Service    frequently 
interrupted  (o) 

(2) 

GRAND   TOTAL                                                                                               PERFECT  SCORE   SO 

252  LIGHT  IN  THE  HOME 

REFERENCE  BOOKS 

Adams,  Harper's  Electricity  Book.    Harper  and  Brothers. 

Bachman,  Great  Inventors  and  their  Inventions  (Edison).  American  Book  Com- 
pany. 

Barber,  First  Course  in  General  Science,  Chapter  I.     Henry  Holt  and  Company, 

Brownell,  General  Science,  Chapter  X.     Blakiston's  Son  and  Company. 

Burns,  Great  Inventions  (Electricity).     Harper  and  Brothers. 

Clark,  An  Introduction  to  Science,  Chapters  XXVI,  XXX.  American  Book  Com- 
pany. 

Gowin  and  Wheatley,  Occupations,  Chapter  IX.     Ginn  and  Company. 

Hodgdon,  Elementary  General  Science,  Chapters  X,  XI.  Hinds,  Hayden,  and 
Eldredge. 

Inventor,  and  Lamp  (Lecture  8).  General  Electric  Lecture  Service,  Schenectady, 
N.  Y. 

Official  Handbook,  Boy  Scouts  of  America.     Doubleday,  Page  and  Company. 

Lynde,  Physics  of  the  Household.     The  Macmillan  Company. 

Smith  and  Jewett,  Introduction  to  the  Study  of  Science,  Chapter  IV.  The  Mac- 
millan Company. 

Tappan,  Modern  Triumphs  (Edison  and  Electric  Light).  Houghton  Mifflin  Com- 
pany. 

Tappan,  Wonders  of  Science.    Houghton  Mifflin  Company. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  XII.  Houghton 
Mifflin  Company. 


CHAPTER   XVI 
IMPORTANCE   OF   OUR   EYES 

Problems.  —  i.  To  see  how  the  eye  resembles  a  camera 
in  structure. 

2.  To  find  out  what  colors  are. 

3.  To  learn  what  the  common  defects  of  the  eye  are  and  how 
to  remedy  them. 

4.  To  find  out  the  defects  of  my  own  eyes. 

5.  To  learn  rules  for  proper  care  of  the  eyes. 

Experiments  and  demonstrations.  —  i.  To  show  how  the  pupil  of  the 
eye  changes  size  in  looking  from  a  dark  room  toward  a  strong  source  of 
light. 

2.   To  test  my  own  eyes  for  defects. 

Project  I.  —  To  REMEDY  ANY  EYE  DEFECTS  YOU  MAY  HAVE. 

1.  Have  a  competent  person  test  your  eyes  for  astigmatism,  near- 
sight,  farsight,  and  color  blindness.    You  can  tell  if  you  have  eye- 
strain. 

2.  Remedy  any  serious  defects. 

3.  Explain  the  science  involved  in  the  eye  defect  and  in  the  appli- 
cation of  the  remedy. 

How  we  see.  —  One  of  the  saddest  results  of  the  World 
War  is  seen  in  a  hospital  where  men  blinded  by  gas  or 
other  causes  grope  their  way  around  in  somber  darkness. 
How  we  pity  them  !  The  loss  of  sight  would  be  one  of  the 
most  terrible  things  that  could  happen  to  us.  Then  why 

253 


254 


IMPORTANCE   OF  OUR  EYES 


should  we  abuse  these  delicate  organs  we  call  the  eyes? 
The  daytime  is  not  long  enough  for  us,  so  we  provide 
ourselves  with  artificial  light  and  keep  our  eyes  at  work 
part  of  the  night.  We  read  fine  print  in  dim  light,  and 
injure  our  eyes  in  a  hundred  ways.  Our  eyes  are  of  so 
much  importance  to  us  that  it  seems  wise  to  devote  an 
entire  chapter  to  them  and  their  care. 

Lenses  and  what  they  do.  —  We  have  all  tried  to  set  fire 
to  a  pile  of  leaves  or  paper  with  a  burning  glass.  An 
ordinary  reading  glass  found  sometimes  on  the  library 
table  is  a  common  example  of  a  simple  lens.  If  we  look 
at  it  in  cross  section,  we  find  that  it  bulges  outward  in  the 
middle  in  both  directions.  We  call  such  a  lens  double  con- 
vex. If  we  hold  such  a  lens  so  that  the  sun  shines  through 

it,  and  move  a  piece  of 
paper  toward  or  away 
from  it,  one  place  will 
be  found  where  only  a 
tiny  spot  will  be  lighted, 
but  this  will  be  ex- 
tremely bright,  and 
enough  heat  may  be 
concentrated  to  set  the 
paper  on  fire.  This 
point  at  which  the  sun's 
rays  have  been  brought 
together  (see  F  in  fig- 
ure) is  called  the  focus. 
When  light  passes 
through  the  air  to  the  glass,  it  moves  in  parallel  rays,  but 
the  glass  bends  the  rays  so  that  they  come  together  at 
one  point.  This  point  is  called  the  principal  focus  of  the 


Which  lens  has  the  shortest   and    which  the 
longest  focal  length  ? 


THE  CAMERA 


255 


Essential  parts  of  a  plate  camera. 


lens,  and  the  distance  from  that  point  to  the  center  of  the 
lens  is  called  the  focal  length.  You  can  easily  measure  the 
focal  length  of  a  lens  by  this  method. 

The  camera.  —  The  study  of  a  camera  will  help  us  to 
understand  the  parts  of  the  eye.  If  we  carefully  note  the 
parts  of  the  camera 
shown  in  the  illus- 
tration, we  find  that 
it  is  a  light-tight  box 
painted  black  on  the 
inside  to  absorb  all 
light  rays,  and  hav- 
ing a  lens,  a  dia- 
phragm for  changing 
the  size  of  the  open- 
ing, and  a  shutter  in 
front  which  controls  the  time  of  the  exposure  of  the  photo- 
graphic plate  or  film  which  is  placed  at  the  opposite  end 
of  the  camera.  In  a  photographer's  camera,  such  as  is 
shown  in  the  illustration,  a  ground  glass  is  placed  at  the 
end  where  the  plate  is  held  when  an  exposure  is  made. 

Experiment.  —  To  show  how  a  lens  is  used  in  focusing 

Materials :   Double  convex  lens.     White  screen.     Large  carbon  bulb. 

1.  Focal  length. 

Hold  a  double  convex  lens  in  sunlight  at  right  angles  to  the  rays. 
Place  a  screen  of  white  paper  back  of  the  lens.  Adjust  the  distance  be- 
tween them  until  the  spot  of  light  (the  sun's  image)  is  the  smallest. 
Measure  the  distance  from  the  lens  to  the  screen.  This  distance  is 
called  the  focal  length  of  the  lens. 

Compare  the  focal  length  of  a  thick  lens  with  that  of  a  thin  lens  by 
this  method. 

2.  Focusing  as  done  in  the  camera. 

Hold  a  double  convex  lens  about  three  times  its  focal  length  from 
a  large  carbon  lamp  which  is  lighted  in  a  dark  room.  Move  a  screen  of. 


256  IMPORTANCE  OF  OUR  EYES 

white  cardboard  back  and  forth  until  a  position  is  found  where  a  sharp 
image  of  the  filament  is  seen  on  the  screen.  Move  the  light  farther  away. 
What  must  you  do  with  the  lens  to  give  a  second  sharp  image  on  the 
screen?  Compare  the  two  images.  Move  the  lens  towards  the  light 
until  an  enlarged  image  results.  Explain  how  this  experiment  illustrates 
the  use  of  a  lens  in  the  ordinary  camera  and  also  in  the  enlarging  camera. 

What  is  color  ?  —  If  you  have  ever  watched  waves  com- 
ing in  to  the  shore,  you  may  have  noticed  that  sometimes 
the  distance  beween  two  successive  waves  is  quite  great, 
and  sometimes  it  is  much  less.  We  have  learned  that 
light  is  caused  by  waves  of  ether  which  come  to  us  from  the 
sun  or  from  other  lighted  objects.  Only  a  very  small 
portion  of  all  the  ether  waves  affect  our  eyes,  and  give  us 
the  sensation  we  call  light.  Ether  waves  producing  light 
differ  in  length,  the  longest  being  one  thirty-three  thou- 
sandth of  an  inch  in  length,  and  the  shortest  that  we  can 
see,  one  sixty-six  thousandth  of  an  inch  in  length.  The 
longest  of  these  visible  waves  causes  the  sensation  of  red, 
and  the  shortest  gives  the  sensation  violet,  while  all  other 
colors  come  between  these.  Color,  then,  is  a  property 
of  light  waves,  and  each  particular  color  is  due  either  to 
waves  of  some  particular  length,  or  to  mixtures  of  waves 
which  produce  different  colors. 

How  we  see  color.  —  When  all  the  different  light  waves 
from  the  sun  are  mixed  together,  white  light  is  pro- 
duced, as  we  see  when  sunlight  is  reflected  by  white  paper. 
White  substances  are  those  which  reflect  all  sunlight. 
Black  objects  are  those  which  absorb  all  of  it.  Any  object 
which  absorbs  all  the  light  waves  except  the  very  long  ones 
is  red,  because  it  reflects  to  your  eyes  only  the  red  waves. 
In  the  same  way,  any  object  which  absorbs  all  the  waves 
except  the  very  short  ones  would  look  violet  in  color. 
This  seems  very  strange,  but  we  can  prove  that  light  is 


STRUCTURE  OF  THE  EYE 


257 


A  prism  separates  white  light  into  colors  of  the  spec- 
trum. 


made  up  of  these  various  colors  by  passing  it  through  a 
prism,  a  triangular  shaped  glass  such  as  we  often  see  in  the 
candelabra  in  old  houses.  If  a  ray  of  sunlight  were 
passed  through  this  prism  to  a  screen  in  a  darkened  room, 
we  could  see  all  the 
rainbow  colors  of  the 
spectrum.  If  we  al- 
lowed this  light  to 
pass  through  a  sec- 
ond prism  placed  in 
a  reversed  direction 
(see  diagram) ,  the 
colors  would  again 
be  brought  together, 
and  passed  out  as  white  light.  The  rainbow  is  nothing 
more  or  less  than  light  passing  through  falling  drops  of 
water,  which  act  as  prisms,  thus  separating  light  into  its 
elements,  red,  orange,  yellow,  green,  blue,  and  violet. 
Structure  of  the  eye.  —  We  are  now  ready  to  learn 

something  about  the 
structure  of  the  eye. 
Our  eyes  are  among 
the  most  delicate  and 
wonderful  structures 
in  the  body.  We 
abuse  them  con- 
stantly, yet  they  serve 
us  well.  Notice  how 


The  spectrum  colors  can  be  reunited  by  a  second 
prism  so  as  to  produce  a  beam  of  white  light. 


well  they  are  protected  by  being  set  in  a  bony  socket,  and 
how  admirably  the  lashes  serve  to  keep  out  dust  and  dirt. 
See,  too,  how  tears  flow  every  time  any  dust  gets  upon 
the  delicate  membranes  of  the  eye.  Also  observe,  how  the 


H.-.WHIT  CIV,   SCI.   IN  THE  HOME — I? 


258  IMPORTANCE  OF  OUR  EYES 

eye  can  be  turned  in  different  directions,  due  to  the  little 
paired  muscles  which  serve  to  move  the  eyeball. 

If  we  study  a  section  as  shown,  by  cutting  the  eyeball 
in  halves  from  front  to  back,  we  find  that  it  is  more  like  the 

camera  than  it  is  on  the 
surface.  In  the  front  there 
is  a  transparent  lens  which 
makes  a  little  picture  at 
the  back  of  the  eye,  just  as 
the  camera  lens  makes  a 
picture.  This  lens,  how- 
ever, is  not  fixed  in  shape 
like  that  of  a  camera,  Lut 

Section  of  the  eye.     Find  the  parts  which       Jc      fl^viKlA       anrl     ic     mxr\p> 
correspond  to  those  in  a  camera. 

thicker  or  thinner  by  move- 
ment of  delicate  muscles,  thus  doing  away  with  the  ne- 
cessity of  moving  the  lens  forward  or  backward  in  order 
to  get  a  picture  in  focus. 

The  main  portion  of  the  eye  is  filled  with  a  colorless 
substance,  the  vitreous  humor,  while  back  of  this  lies  a 
pigmented  receiving  organ  connected  by  nerves  with  the 
brain,  known  as  the  retina.  It  is  on  this  sensitive  surface 
that  our  images  are  received  and  sent  to  the  brain  by  the 
optic  nerve,  so  that  we  really  see  in  the  brain,  although  the 
picture  is  received  on  the  retina.  There  are  three  coats 
covering  the  eyeball,  a  tough  outer  coat,  the  sclerotic,  a 
middle  coat,  the  choroid,  while  the  inner  coat  is  the  retina. 
These  coats  are  open  at  the  front,  and  the  choroid,  which 
is  filled  with  pigment,  or  color-bearing  material,  makes  a 
kind  of  curtain.  It  is  this  curtain,  called  the  iris,  which 
gives  the  color  to  a  person's  eye.  The  iris  controls  the 
amount  of  light  which  passes  through  the  hole,  or  pupil, 


HOW  THE  EYE  ADAPTS  ITSELF  259 

into  the  inside  of  the  eye,  just  as  the  diaphragm  in  the 
camera  controls  the  light.  On  a  bright  day,  would  you 
expect  the  pupil  of  the  eye  to  be  larger  or  smaller  than  on 
a  dull  day?  Why? 

Experiment.  —  To  see  the  pupil  of  the  eye  change  in  size. 

From  a  room  in  which  all  the  other  windows  are  darkened  look  out  of  the 
window  into  a  very  bright  sky  for  a  moment.  Examine  the  eye  in  a 
mirror.  Then  turn  quickly  and  look  at  your  eyes  in  the  mirror  with 
your  back  to  the  light.  Result?  Explain. 

Control  of  focusing.  —  The  eye  adjusts  itself  quickly 
to  see  objects  at  different  distances.  This  is  done  by 
means  of  tiny  muscles  called  the  ciliary  muscles,  which 
change  the  thickness  of  the  lens.  A  flat  lens  focuses  well 
on  distant  objects,  while  a  thick  lens  focuses  on  objects 
near  at  hand.  If  you  look  at  an  object  some  distance 
off,  and  then  suddenly  holding  a  book  before  your  eyes  try 
to  focus  on  the  page,  you  will  find  that  the  print  is  blurred 
for  a  moment  before  you  are  able  to  see.  This  change  of 
focus  is  called  accommodation. 

How  the  eye  adapts  itself  to  different  intensities  of 
light.  —  It  has  been  found  that  different  intensities  of 
light  in  the  home  are  desirable  for  different  kinds  of  work. 
The  following  table  gives  the  intensity  in  foot  candles, 
which  means  the  amount  of  light  a  candle  would  give  at  a 
distance  of  one  foot  from  an  object. 


DESIRABLE  AT  TIMES 

MINIMUM 

Hall  and  stairways  .     . 
Living  room  and  dining 
room            .     .          , 

i  —  2.5  foot  candles 
3  —  6     foot  candles 

0.5  foot  candle 
i  5  foot  candles 

Sewing  room  .... 

6  —  12  foot  candles 

3.    foot  candles 

260  IMPORTANCE  OF  OUR  EYES 

The  eye  is  able  to  adjust  itself  to  different  amounts  of  light, 
within  rather  wide  limits,  without  harm.  In  order  to  avoid 

straining  the  eye,  it 
is  necessary  to  have 
enough  light.  Much 
harm  is  sometimes 
done  when  we  are 
young  by  trying  to 

How  does  the  eye  adjust  itself  to  different  intensities      read     hi     insufficient 
of  light  ?  T  .    ,    .  , 

light ;  just  as  much 

harm  has  been  done  by  looking  into  a  blinding  light,  or 
trying  to  look  at  the  sun,  as  some  youngsters  do  at  times 
to  "  stunt  "  each  other. 

Some  defects  of  the  eye.  —  Although  the  eye  is  a  wonder- 
ful piece  of  mechanism,  it  has  several  common  defects. 
Fortunately,  due  to  a  study  of  the  eye  and  of  the  science 
called  optics,  we  are  now  able  to  remedy  most  of  these  de- 
fects very  easily,  especially  by  the  use  of  glasses.  It  is 
estimated  that  one  person  in  every  four  has  some  defect 
in  vision.  Nearly  twenty-five  per  cent  of  the  school  chil- 
dren in  Massachusetts  and  over  thirty  per  cent  of  the 
school  children  in  New  York  have  eye  trouble  of  some 
kind.  The  most  common  defect  of  the  eye  is  astigmatism. 
This  is  usually  due  to  a  slight  uneven  curvature  of  the 
cornea,  or  the  lens.  It  can  easily  be  discovered  by  use  of 
the  diagram  on  page  26 1 .  Look  at  either  of  the  figures  with 
one  eye  closed.  If  some  of  the  lines  appear  blurred  or 
thicker  than  others  astigmatism  is  present  and  should  be 
corrected  with  glasses,  as  this  defect  is  a  frequent  cause 
of  headache. 

The  next  most  common  defect  is  nearsightedness.  In 
this  case  the  eyeball  is  too  long  from  front  to  back,  or  the 


SOME  DEFECTS  OF  THE  EYE 


261 


Diagrams  to  be  used  in  testing  for  astigmatism. 

lens  is  too  thick,  so  that  the  image  of  distant  objects  is 
focused  in  front  of  the  retina.  This  tends  to  make  one 
squint  the  eye,  and  also  to  hold  the  object  near  to  the 
eye.  Nearsightedness  is  quite  common  in  children,  and  is 
easily  corrected  by  the  use  of  glasses  which  place  the  focus 
in  the  right  place. 


Nearsightedness  is  remedied  by  means  of  concave  eyeglass  lenses. 

Farsightedness  is  another  common  defect.  In  farsighted- 
ness, the  eyeball  is  too  short,  or  the  lens  too  thin,  and  the 
image  if  it  could  be  found  would  fall  behind  the  retina. 
Hence  we  get  a  blur  on  the  retina.  This  is  a  more  diffi- 
cult defect  to  recognize,  because  people  often  do  not  know 
its  presence  until  they  are  made  aware  of  it  by  constant 
headaches.  As  a  person  grows  older,  he  has  a  tendency 
to  become  farsighted.  It  is  frequently  the  case  that  elderly 
persons  when  reading  need  one  kind  of  lens,  and  for  or- 
dinary purposes,  a  second  lens.  For  this  purpose  a  double 


262  IMPORTANCE  OF  OUR  EYES 

glass,  called  bifocal,  combining  the  two  lenses  in  one  is 
often  used. 


Farsightedness  is  remedied  by  means  of  convex  eyeglass  lenses. 

Testing  of  eye  defects.  —  A  very  simple  exercise  for 
testing  most  eye  defects  is  given  in  the  following  labora- 
tory experiment.1 

Experiment.  —  To  test  my  own  eyes  for  defects. 


Y  F  E  V 


A.  Test  for  Farsightedness 

Method:  Using  the  Snellen  test  cards,  locate  the  finest  line  that  can 
be  read  at  a  distance  of  20  feet.  Test  each  eye  separately,  covering  the 

eye  not  in  use  with 
a  piece  of  cardboard. 
Then  place  a  pair  of 

How  far  away  can  you  read  these  letters?    Measure      sPectacles   Wlth  a  5° 
the  distance.    Twenty  feet  is  a  test  for  the  normal     plus  diopter  lens  be- 
fore the  eyes.     If  as 

fine  or  a  finer  line  can  now  be  read,  then  farsightedness  is  present  and  an 
oculist  should  be  consulted,  especially  if  headaches  or  other  symptoms 
of  eye  defects  are  present.  Farsightedness  is  one  of  the  most  frequent 
causes  of  eyestrain  and  is  hard  to  detect  because  the  eyesight  seems 
.so  good. 

B.  Test  for  Nearsightedness 

Method:  Use  the  above-mentioned  charts.  Determine  the  finest  type 
you  can  read  at  a  distance  of  20  feet.  If  it  is  larger  than  the  20/20 
line,  then  your  vision  is  defective  and  you  should  probably  consult 
an  oculist,  especially  if  you  have  any  symptoms  of  eyestrain. 

1  This  test  was  prepared  by  Dr.  Lucius  J.  Mason  of  the  Department  of 
Biology,  DeWitt  Clinton  High  School,  New  York. 


EYESTRAIN  263 

C.   Test  for  Astigmatism 

Method:  Use  the  clock  dial  disk  at  20  feet.  If  some  lines  are  blacker 
than  others,  then  astigmatism  is  present.  If  headaches  or  other  symp- 
toms are  present,  then  you  should  consult  an  oculist  and  have  glasses 
fitted  to  correct  this  trouble. 

Eyestrain.  —  Eyestrain  frequently  results  from  attempts 
to  overcome  defects  of  the  eye,  and  also  by  putting  the 
eyes  to  too  severe  use,  thus  taxing  the  blood  vessels  of  the 
eye,  and  the  nerves,  which  in  turn  affect  the  nerves  of 
the  head  and  stomach.  The  following  are  some  of  the 
things  which  we  often  call  upon  the  eye  to  do : 

1.  Change  focus  for  different  words  in  the  line.     This  is 
because  they  vary  in  their  distance  from  the  eye,  and  only 
in  two  places  are  the  eyes  equally  distant  from  the  words 
being  read. 

2.  Insufficient  light.     The  illumination  of  the  object  is 
of  extreme  importance  as  the  light  fades  at  close  of  day. 
For  then  the  white  paper  of  a  printed  page  becomes  darker 
and  darker,  until  finally  it  reflects  very  little  more  light  to 
the  eye  than  the  printed  letters ;   consequently  the  letters 
no  longer  stand  out,  and  we  have  great  eyestrain. 

3.  The    wrong   position   produces    glare.     One    of   the 
most  frequent  errors  around  the  home  table  is  that  boys 
and  girls  frequently  face  the  light  rather  than  allow  it  to 
come  over  the  shoulder,  or  from  above.     Overhead  light- 
ing systems  are  far  better  than  any  light  which  throws  a 
glare  on  the  paper.     Reading  in  an  unsteady  or  flickering 
light,  particularly  on  moving  trains,  is  extremely  bad  for 
the  eye. 

4.  Too  much  light  in  the  field  of  vision  is  as  bad  as  too 
little  light.      For  most  purposes   the   student    lamp,   in- 
candescent electric  light,  and  Welsbach  gas  light  of  mod- 


264  IMPORTANCE   OF   OUR   EYES 

erate  intensity  are  preferred  to  the  stronger  lights.  Fine 
print  and  the  use  of  glossy  or  colored  papers  are  also  matters 
that  we  should  avoid.  The  use  of  large  type  for  young 
children  is  particularly  important,  because  the  eye  then  is 
more  elastic,  and  extra  strain  placed  on  the  muscles  of  the 
eye  may  lead  to  permanent  harm  to  the  curved  surfaces. 

Color  blindness.  —  In  order  to  qualify  as  an  engineer 
on  the  trains,  or  as  pilot,  where  it  is  necessary  to  distin- 
guish colors,  one  must  first  submit  to  a  test  for  color  blind- 
ness.1 From  three  to  four  per  cent  of  boys  and  about 
one  per  cent  of  girls  are  color  blind.  This  is  one  reason 
why  some  boys  cannot  match  colors  as  well  as  girls  can. 
The  most  common  form  of  color  blindness  is  the  inability  to 
distinguish  between  red  and  green. 

Suggestions  for  the  care  of  the  eye.  —  i.  Do  not  sit  so 
that  direct  light  reflected  from  book,  paper,  or  highly 
polished  floors  will  cause  a  glare. 

2.  Do  not  sit  facing  strong  artificial  or  natural  light. 

3.  Do  not  sit  so  that  your  shadow  falls  upon  your  work. 

4.  Do  not  use  a  flickering  light. 

5.  Do  not  read  on  a  train  or  other  moving  conveyance. 

6.  Adjust  the  intensity  of  the  light  to  your  needs. 
Strong  light  is  needed  to  read  fine  print. 

7.  Do  not  use  the  eyes  when  they  ache  or  when  you 
yourself  are  fatigued. 

Correction  of  defects.  —  If  you  have  discovered  from 
the  laboratory  exercises  that  you  have  eye  defects,  go  at 
once  to  an  oculist  and  have  glasses  to  correct  them. 

If  the  eyes  are  red  or  inflamed  or  if  water  runs  from 
them,  or  if  the  lids  are  sore,  see  a  physician  at  once.  Avoid 

1  Holmgren's  woolens  and  Westcott's  color  slide  are  useful  in  detecting 
color  blindness. 


REMOVAL  OF   CINDERS  265 

doing  fine  work  and  reading  in  bad  light.  If  the  eyes 
pain,  use  a  cloth  heated  with  very  hot  water.  A  two  per 
cent  boracic  acid  solution  is  an  excellent  wash,  and  may 
be  used  frequently.  This,  or  a  salt  solution  made  of  one 
teaspoonful  of  salt  to  a  pint  of  boiling  water,  may  be  used 
to  wash  the  eye  after  getting  a  cinder  in  it. 

Removal  of  cinders.  —  Sometimes  particles  of  dust 
or  cinders  get  into  the  eye.  These  are  usually  washed 
out  by  tears  which  flow  as  a  result  of  the  irritation.  Some- 
times, however,  they  have  to  be  removed.  In  the  case 
of  the  lower  lid,  there  is  little  trouble ;  if  one  pulls  the  lid 
down  the  speck  can  easily  be  removed  with  the  use  of  a 
clean  handkerchief.  The  upper  lid  is  more  difficult  to 
pull  back.  In  order  to  do  this  successfully,  have  the 
person  look  downward,  place  a 
small  pencil  against  the  upper 
portion  of  the  lid,  take  hold  of 
the  eyelashes,  turn  the  lid  up- 
ward and  back  over  the  pencil, 


and  the  lid  is  in  such  a  position  Turnin* the  ^  back  to  remove 
that  the  speck  can  easily  be  lo- 
cated. Sometimes  a  tiny  sharp-pointed  bit  of  glass  or  cinder 
becomes  embedded  in  the  surface  of  the  cornea.  A  drop  of 
olive  oil  in  the  eye  prevent*  irritation  until  with  the  help  of 
an  expert  physician  it  can  be  removed. 

REFERENCE  BOOKS 

Allen,  Civics  and  Health  (For  teachers),  Chapter  VII.     Ginn  and  Company. 

Brownell,  General  Science,  Chapter  I.    Blakiston's  Son  and  Company. 

Clark,  Introduction  to  Science,  Chapters  XXVI,  XXVIII,  XXIX.    American  Book 

Company. 

Hodgdon,  Elementary  General  Science,  Chapter  X.     Hinds,  Hayden,  and  Eldredge. 
Hunter,  A  Civic  Biology,  Chapter  XXIII.     American  Book  Company. 


266 


IMPORTANCE   OF  OUR  EYES 


Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapter  XXIV.     American  Book 

Company. 

Ritchie,  Physiology  and  Sanitation  (Chapter  on  Eye).     World  Book  Company. 
Routledge,  Discoveries  and  Inventions  of  the  Nineteenth  Century,  pages  374-402 ; 

529-551.     Routledge. 

Stiles,  Human  Physiology,  Chapter  XI.    W.  S.  Saunders  Company. 
Thompson,  Boys'  Book  of  Sports,  pages  291-301.     Century  Company. 


SCORE  CARD.     CARE  OF  MY  EYES 


SCORE 


Perfect 
Score 


My 

Score 


Use  different  intensities  of  light  for  different  kinds  of  work. 

(See  table,  page  259) 2.5 

Never  look  into  "  blinding  "  light 2.5 

Do  not  use  flickering  light,  for  work 2.5 

Do  not  use  dim  light  for  reading 2.5 

Do  not  read  on  cars 2.5 

Correct  position  of  light  when  reading.  (No  glare  on 

paper;  light  from  above) .  .  2.5 

Correct  position  of  light  when  writing.  (Light  over  left 

shoulder  for  right-handed  people) 2.5 

Do  not  read  fine  print  for  long  period  of  time  ....  2.5 
Do  not  use  too  strong  a  light  for  reading.  Lights  that 

make  glare  are  bad  2.5 

Never  face  strong  light  when  reading  or  doing  other  fine 

work 2.5 

Strong  light  used  for  sewing  or  other  fine.work  ....  2.5 

Do  not  use  eyes  when  they  ache  2.5 

Do  not  use  eyes  when  tired  2.5 

Bathe  eyes  in  hot  salt  water  if  they  ache 2.5 

Wash  frequently  in  boracic  acid  if  inflamed 2.5 

Can  remove  dirt  by  rolling  lid 2.5 

Eyes  examined  by  oculist  once  a  year 2.5 

Glasses  adjusted  by  oculist,  when  needed    .     .     ....  2.5 

Glasses  used  constantly  in  case  of  eye  defects  .  .  .  .  2.5 

Eyes  tested  and  found  glasses  not  needed 2.5 

TOTAL 50.0 


PART   V.     THE    HOME   AND    ITS 
SURROUNDINGS 

CHAPTER  XVII 
MAKING   AND   BEAUTIFYING   THE   HOME 

Problems.  —  i.    To  find  out  the  chief  materials  of  which 
our  houses  are  made. 

2.  To  see  what  arrangement  of  rooms  in  the  house  is  de- 
sirable. 

3.  To  learn  what  the  essential  qualities  of  the  important 
rooms  in  the  house  are. 

4.  To  see  what  decorations  can  be  used  to  make  the  house 
beautiful. 

Experiments.  —  i.   To  discover  the  relation  of  markings  in  trim  to  the 
cutting  of  wood. 

2.   To  make  concrete  of  various  mixtures  and  compare  properties. 

Project  I.  —  To  PLAN  THE  IDEAL  HOUSE. 

1.  Make  floor  plans  of  your  own  house. 

2.  Study  plans  made  by  others.     Cut  plans  and  photos  from  maga- 
zines.   What  are  their  good  and  their  bad  features  ? 

3.  Study  your  friends'  houses. 

4.  Finally  make  floor  plans  for  what  you  consider  an  ideal  house 
for  your  own  family. 

5.  Discuss  materials  you  would  select  for  building  and  give  rea- 
sons, and  tell  how  you  would  decorate  the  house  within. 

267 


268        MAKING  AND   BEAUTIFYING  THE  HOME 

6.  Discuss  the  wall  papers  and  decorations  used  in  the  different 
rooms. 

7.  Get  furniture  catalogues  and  make  selection  of  ideal  furnish- 
ings for  each  room  in  the  house. 

8.  Report  on  your  project  in  class. 

Homes  of  to-day.  —  We  know  that  homes  of  the  present 
day  are  very  different  from  what  they  were  when  primi- 
tive man  lived  on  the  earth.  The  complexities  of  mod- 
ern life  have  made  so  many  demands  that  now  the  home  is 

a  very  different  place 
from  what  it  was  even 
a  generation  ago.  No 
two  homes  are  alike. 
Each  one  should  be 
suited  to  the  locality 
and  to  the  people  who 
live  in  it  whether  it  be 
on  the  farm,  in  a  town, 
or  in  the  big  city.  One 
of  us  may  live  in  a 
frame  house,  another  in 
a  brick  row,  and  a  third 

Annual  rings  shown  in  cross  section  of  wood. 

in    an    apartment    or 

tenement,  but  wherever  we  live,  our  home  is  the  place  where 
we  sleep  at  night,  where  we  eat,  and  best  of  all,  where 
family  life  centers.  The  purpose  of  this  chapter  is  first, 
to  learn  something  about  the  materials  out  of  which  our 
houses  are  constructed,  and  then  something  about  the 
decoration  of  the  home  and  its  grounds. 

Building  materials.  —  If  you  make  a  list  of  all  the 
materials  that  are  used  in  building  a  house  you  find  that 
wood,  stone,  glass,  concrete,  and  metals  have  an  important 


BUILDING  MATERIALS 


269 


part.  Wood  is  still  one  of  the  most  used  building  ma- 
terials in  this  country.  Frame  houses  are  much  more 
numerous  than  those  of  brick,  stone,  and  concrete.  The 
quality  of  the  wood  depends  on  the  kind  of  tree  which 
produces  it,  and  the  beautiful  grain  that  is  visible  in  some 
woods  is  nothing  more  or  less  than  the  so-called  annual 
rings  which  appear  as  a  result  of  growth  in  certain  kinds  of 
trees.  The  material  in  the  board  or  beam  or  in  the  mold- 
ing or  mantle  of  a  room  is  composed  of  millions  of  dead 
cells,  the  walls  of  which  only  remain.  These  walls  are 
hollow,  living  matter  has  gone  from  them,  and  when 
wood  is,  finished,  these  holes  are  filled  up  with  paint,  oil, 
wax,  varnish,  and  whatever  substance  is  used  to  give  wood 
its  finished  appearance.  Although  wood  is  necessary  for 
some  parts  of  the  house,  it  is  not  the  safest  material  for 
construction  because  of  its  liability  to  burn.  Wooden 
shingles  should  be  treated  with  a  solution  to  make  them 
wear  longer,  and  to  protect 
us  from  fire. 


Experiment.  —  To  show  the  rela- 
tion of  the  markings  in  trim 
to  the  cutting  of  wood. 

Materials :     Diagrams,     school 

furniture.     Hough's    sections 

of  woods. 
Method :  Examine  the  sections 

shown   you.     Compare   with 

figure    showing  cross   section 

radial  and  tangential  cutting 

of  timber. 

Note :  Most  lumber  is  cut  tangentially .  Hence  the  yearly  rings  take 

a  more  or  less  irregular  course.     The  grain  of  wood  is  caused  by  the  fibers 

not  taking  straight  lines  in  their  course  in  the  tree  trunk.     In  many  cases 

the  fibers  of  the  wood  take  a  spiral  course  up  the  trunk,  or  they  may  wave 

outward  to  form  little  projections.   Boards  cut  from  trees  with  irregular 


Diagrams  of  sections  of  timber,     a,  Cross 
section,     b,  Radial,     c,  Tangentials. 


270        MAKING  AND   BEAUTIFYING  THE  HOME 

fibers  will  show  the  effect  seen  in  many  of  the  school  desks,  where  the 
annual  rings  appear  to  form  small  elliptical  markings. 

Study  the  top  of  your  desk,  the  wainscoting,  the  floor,  and  any  other 
wood  at  hand  to  determine  the  plane  at  which  it  was  cut.  Study  the 
figures  and  compare  with  the  specimens  of  wood  just  noted.  Can  you 
observe  any  difference  in  the  color  of  the  wood  ? 

Conclusion:  What  is  the  common  method  of  cutting  wood  for  trim? 
Why?  Does  most  dried  wood  show  any  difference  between  heart  and 
sap  wood?  What  is  this  difference? 


A  granite  quarry. 

Stone  as  building  material.  —  Although  not  many  single 
houses  are  built  of  stone,  yet  in  some  parts  of  the  coun- 
try, where  it  can  be  obtained  easily,  stone  makes  an  ex- 
cellent building  material.  Many  an  old  house  in  New  Eng- 
land was  built  in  part,  at  least,  from  the  bowlders  and 
loose  stones  which  were  found  scattered  around  in  the 
vicinity.  About  eighty  millions  of  dollars'  worth  of  stone 
is  used  in  this  country  every  year.  Most  of  it  is  lime- 
stone, sandstone,  or  granite.  Limestone  is  found  in  many 
parts  of  the  United  States,  and  while  much  of  it  is  used, 
as  the  Indiana  limestone,  for  buildings,  far  more  is  used  now 


ARTIFICIAL  STONE  271 

in  the  manufacture  of  lime  for  cement  and  fertilizer.  Sand- 
stone is  easily  quarried,  and  some  kinds  are  very  durable. 
The  brownstone  houses  in  many  cities  show  early  signs 
of  decay ;  this  is  because  of  a  poor  grade  of  stone  having 
been  used.  The  "  life  "  of  a  building  stone  is  the  length 
of  time  before  it  shows  signs  of  crumbling  or  chipping. 
Compare  the  life  of  building  stones  as  given  in  the  fol- 
lowing table.  Granite,  although  extremely  hard  and  du- 
rable, is  not  very  desirable  for  small  houses.  Slate  is  used 
for  roofing  many  houses.  While  it  makes  a  hot  roof,  it 
also  makes  a  safe  and  durable  one. 


STONE 

LIFE  IN  YEARS 

Micaceous  limestone      
Micaceous  brownstone  (sandstone) 
Compact  brownstone  (sandstone)    . 
Marble 

2  to     15 
15  to    30 
15  to    30 
40  to    80 

Fine  marble      

50  to  100 

Granite    

57  to  200 

Artificial  stone.  —  We  are  coming  more  and  more  to  use 
cement,  hollow  tile,  and  concrete  in  the  construction  of 
our  houses.  Some  of  the  most  beautiful,  as  well  as  econom- 
ical, small  houses  are  now  made  of  concrete  or  hollow  tile, 
with  a  coating  of  stucco,  a  kind  of  plaster  which  is  placed 
over  the  outside  of  the  house.  It  has  the  advantage  when 
used,  over  wooden  houses,  of  giving  protection  against  fire. 
Lime  and  sand  are  important  building  materials  also. 
Ordinary  mortar  made  by  mixing  lime  with  sand  and 
water  hardens  more  slowly  than  cement,  the  hardening 
being  caused  by  the  taking  up  of  carbon  dioxide,  which 
changes  the  lime  to  calcium  carbonate,  or  as  the  mason 


272        MAKING  AND   BEAUTIFYING  THE  HOME 


says,   "  causes   it  to  set."     Many   of   our   tall  buildings, 
as  the  "  skyscraper  "  shown  in  the  illustration,  are  made 

of  concrete,  built  upon 
rods  of  steel  and  wire 
mesh.  Concrete,  as  we 
know,  has  recently  come 
into  use  even  for  build- 
ing ships,  and  many 
other  different  uses  are 
made  of  it. 

Experiment.  —  To  make  con- 
crete of  various  mix- 
tures and  to  compare 
properties. 

Materials:  Portland  cement. 
Sand.  Steel  knitting  nee- 
dles. Frame  with  six  com- 
partments, each  about  i£ 
inches  deep,  i  inch  wide, 
and  10  inches  long.  Mix 
sand  and  cement  dry, 
in  proportions  indicated. 

Then  add  water  to  make  a  pasty  mass  which  slides  easily  from  the 
trowel.  Make  the  following  mixtures  and  pour  them  into  the 
frames : 


A  skyscraper,  built  mostly  of  concrete. 


TEST 

CEMENT 

SAND 

i  

All  cement 

o 

2  '•-_*.- 
2 

i  part  cement 
i  part  cement 

2  parts 
4  parts 

A 

i  part  cement 

6  parts 

5-1       ....'.   .,    ,,    g 

62 

i  part  cement 
i  part  cement 

5  parts 
6  parts 

1  Reinforce  by  putting  in  five  steel  knitting  needles  well  spaced. 

2  Instead  of  using  sand  use  dark  earth  or  loam. 


GLASS  IN  THE  HOME 


273 


Let  the  mixtures  harden  from  three  to  four  weeks.  Examine  for  ap- 
pearance. Test  for  strength.  If  supported  at  the  ends,  how  much  weight 
across  can  be  supported?  Conclusions? 

Brick  houses.  —  Many  of  us  who  dwell  in  cities,  and  some 
of  us  who  live  where  clay  is  abundant,  may  live  in  brick 
houses.  Bricks,  as 
most  of  us  know, 
are  made  from  wet 
clay  which  is  ground, 
placed  in  molds  and 
then  baked.  All 
bricks  must  be 
baked,  and  by  vari- 
ous processes,  a  glaze 
is  put  on  the  outside 
of  some,  which  ren- 
ders them  more  or 
less  waterproof .  Or- 
dinary bricks,  as  one 
can  prove  by  an  ex- 
periment, take  up  a 
great  deal  of  water, 
and  therefore  are  Brickmaking. 

apt  to  crack  and  crumble  in  very  cold  regions. 

Glass  in  the  home.  —  We  do  not  always  think  of  glass 
as  a  building  material,  yet  it  is  a  very  important  one,  as 
there  is  no  satisfactory  substitute  for  it.  In  these  days  of 
sun  parlors,  large  windows,  and  inclosed  porches,  glass  is 
more  and  more  extensively  used.  Window  glass  is  manu- 
factured out  of  sand  mixed  with  lime  and  compounds  of 
soda,  melted  at  a  high  temperature,  and  then  blown  by 
machinery  into  great  cylinders  which  are  later .  cut  and 

H.-WHIT.   CIV.   SCI.   IN  THE  HOME  —  l8 


274        MAKING  AND   BEAUTIFYING  THE   HOME 

placed  in  furnaces,  flattened  out,  smoothed  off,  and  finally 
cut  into  sizes  used  by  the  trade. 

Choosing  a  home.  —  Although  boys  and  girls  do  not 
often  have  an  opportunity  to  choose  their  own  homes, 
yet  it  is  always  well  to  have  reasons  for  selecting  one's 
neighborhood.  There  are  many  advantages  in  the  city 
which  are  often  lacking  in  the  country,  such  as  paved 


A  well-kept  country  home. 

streets,  sidewalks,  good  schools,  churches,  and  theaters, 
and  above  all  ample  protection  against  disease  in  the  form 
of  good  water  supplies,  sewage  systems,  and  a  Board  of 
Health.  Yet  on  the  whole,  most  boys  and  girls  prefer  to 
live  in  the  country.  For  here  we  find  fresh  air  and  sun- 
shine and  room  for  games.  Here  we  may  keep  pets. 
Here  we  may  have  a  garden  and  orchard,  and  here  are 
walking  and  riding,  swimming,  boating,  hiking,  and  picnick- 
ing, pleasures  which  all  country  boys  and  girls  know.  A 
detached  house  has  its  advantages,  as  well  as  its  disadvan- 


THE  FLOORS  OF  A  HOUSE 


275 


tages.  It  is  preferable  to  a  large  apartment  or  tenement 
house  five,  six  or  twenty -five  stories  high,  with  dark  halls 
and  tiny  rooms. 

A  well-planned  house.  —  We  may  not  be  able  to  own 
the  house  in  which  we  live,  still,  since  we  are  aiming  at 
ideal  conditions,  we  ought  to  know  something  about  house 
planning.  A  study  of  the  accompanying  diagram  will 


UVING!?OOM     HAU, 


In  what  respects  is  this  a  good  first  floor  plan  ?    Has  it  any  defects  1     (After 
Van  Rensselaer.) 

show  us  a  well-planned  small  house.  What  rooms  are 
necessary?  What  rooms  could  be  dispensed  with?  In 
a  well-planned  house,  we  have  a  hall,  living  room,  dining 
room,  kitchen,  and  closets  on  the  first  floor,  bedrooms 
and  bath  on  the  second  floor,  and  a  well-ventilated  base- 
ment which  is  provided  with  a  heating  apparatus,  vege- 
table closet,  storage  room,  and  laundry. 

The  floors  of  a  house.  —  Floors  to  be  durable  should 
be  made  of  hard  wood,  and  should  have  an  inconspicuous 


276        MAKING  AND   BEAUTIFYING  THE  HOME 


iiii 


raLle. 
thin 


grain.  Where  soft  wood  is  used,  the  cracks  may  be  filled 
with  crack  filler,  which  can  be  made  at  home  of  a  combina- 
tion of  flour  paste  and  the  pulp  of  damp  newspaper,  and 
the  floors  then  given  two  or  three  coats  of  hard  paint  to 

make    them    more    du- 
Rugs  are  better 
carpets,     because 
they  can  be  more  easily 
cleaned  and  thus  some 
of  the  dangers  from  dust 
are  avoided. 

Color  in  the  home.  - 
How  many  times  have 
you   gone  into  a  home 

Types  of  artistic  rugs.  Only  part  of  rugs  shown.      where   ^    strange    CQm_ 

bination  of  color  of  the  wood,  wall  paper,  and  hangings  of- 
fended the  eyes,  and  how  often  have  you  gone  into  a  home 
in  which  the  paper  and  woodwork  blend,  thus  giving  a  feel- 
ing of  comfort  and  homelike  warmth  !  One  reason  why  one 
room  is  light  and  another  dark  is  the  amount  of  sunlight 
absorbed  by  the  walls.  A  glance  at  the  following  table  will 
give  some  idea  of  how  this  differs : 

Amount  of  Sunlight  Absorbed  by  Various  Materials 


Clean  glass      .    .  -'.     .     .  5  % 

White  paper 18% 

Newspaper 4°% 

Pink  wall  paper 50% 

Yellow  wall  paper    ....  60% 


Dark  brown  wall  paper      .     .  87  % 

Dark  green  wall  paper   .     .     .  95  % 

Deep  blue  wall  paper     .     .     .  96  % 

Navy  blue  cloth        ....  98  % 

Black  velvet    .     .'.     .     .     .  99% 


To  make  a  room  bright  and  cheerful  in  the  evening, 
remember  that  colors  do  not  have  the  same  value  in 
artificial  as  in  natural  light,  for  example,  blue  objects  lose 


THE  IDEAL  BEDROOM 


277 


some  of  their  richness  in  an  artificial  light.  Blue  is  a  cold 
color  and  may  be  used  in  a  bright,  sunny  room.  Red  and 
yellow  are  warm  and  help  to  lighten  rooms  which  are 
naturally  dark.  Light  colors  increase  the  apparent  size 
of  a  room  and  give  it  the  effect  of  cleanliness  and  good 
cheer.  While  dark  colors  make  a  room  seem  smaller, 
and  while  they,  produce  an  effect  of  dignity  and  richness, 
very  often  they  make  a  room  look  gloomy,  and  make  it 
difficult  to  light.  Wall 
papers  in  general  are 
more  restful  and  better 
for  the  eyes  if  used  in 
plain  colors,  such  as 
tans,  buffs,  blues,  and 
reds.  Papers  with  a 
gaudy  pattern  in  which 
there  is  much  contrast 
are  not  restful  to  the 
eye,  nor  do  they  make  a 
good  background  for  pictures.  Rough  papers  collect  the 
dust  and  are  hard  to  clean.  In  a  rented  house,  one  should 
insist  that  the  papers  in  the  bedrooms  be  changed,  and  if 
possible,  have  the  kitchen  walls  thoroughly  painted  before 
taking  possession.  Can  you  see  why  ? 

The  ideal  bedroom.  —  Did  you  ever  think  that  you 
spend  about  a  third  of  your  life  in  your  bedroom  ?  Since 
this  is  so,  a  bedroom  is  a  very  important  place  and  we 
should  treat  it  as  such.  Pure  and  sufficient  air  is  most 
important.  Our  bedroom  should  have  at  least  one  large 
window,  and  if  possible,  two.  At  night,  even  in  the 
winter  time,  these  windows  should  be  open,  both  top  and 
bottom,  so  that  a  current  of  cool,  pure,  and  fresh  air  may 


Which  wall  paper  makes  the  most  pleasing  back- 
ground ? 


278 


MAKING  AND  BEAUTIFYING  THE  HOME 


come  to  us  while  we  sleep.  As  a  rule  air  is  purer  at  night 
than  in  the  daytime,  especially  in  the  city,  because  at 
that  time  there  is  less  dust  and  smoke  in  it.  We  should 
avoid  drafts  in  our  ideal  bedroom ;  this  can  be  done  by 
placing  a  screen  in  front  of  the  window.  The  furnish- 
ings, even  for  the  girl  who  likes  pretty  things,  should  be 


Name  the  good  points  of  this  bedroom. 

plain  and  simple.  There  should  be  few  hangings  as  they 
collect  dust  and  dirt.  It  is  better  to  have  the  walls  painted 
thani  papered,  especially  in  a  rented  house.  Do  you  see 
why?  The  floor  should  be  uncarpeted,  painted  or  waxed, 
and  have  movable  rugs,  so  that  it  may  easily  be  kept 
clean  and  sweet.  A  painted  iron  bedstead,  with  movable 
springs  and  a  moderately  hard  mattress,  makes  the  best 
bed  for  young  growing  boys  and  girls.  If  you  study  in 


THE  LIVING  ROOM 


279 


your  room,  a  shaded  electric  bulb,  gas  mantle  or  oil  lamp 
gives  a  satisfactory  light. 

The  living  room.  —  What  is  jollier  than  a  family  party 
grouped  around  a  fireplace  in  the  living  room?  A 
living  room  without  a  fireplace  can  be  made  attractive 
and  homelike  with  a  big  table,  plenty  of  books,  a  well- 
placed  central  light  around  which  the  family  can  gather  in 


Why  is  this  an  ideal  living  room  ? 

the  evening,  and  a  few  good  pictures  and  hangings  on  the 
wall.  The  wall  paper  should  be  plain  rather  than  fig- 
ured, and  not  so  highly  colored  that  it  is  not  restful  to  the 
eye.  A  large  rug  rather  than  a  carpet  should  partly  cover 
the  floor.  There  should  be  a  comfortable  chair  for  each 
member  of  the  family,  bookcases  filled  with  favorite  books, 
and  a  comfortable  couch. 

The  ideal  dining  room.  —  Here,  as  in  the  living  room, 
the  furniture  should  be  comfortable  and  homelike.     The 


280         MAKING  AND  BEAUTIFYING  THE  HOME 

table  should  be  large  enough  for  all  to  have  plenty  of  space, 
and  the  dishes  and  glassware  should  be  abundant.  Re- 
member that  cleanliness  of  dishes,  utensils,  and  food, 
will  go  a  long  way  in  keeping  us  well,  especially  during 


An  ideal  dining  room. 

hot  weather.  Flies  must  be  kept  away  from  the  food  and 
dishes,  for  flies  are  disease  carriers.  There  should  be  a 
closed  china  closet  in  the  room,  so  that  dishes  will  be 
kept  free  from  dust  and  flies.  The  draperies  should  be  few, 
and  the  floor  bare  or  covered  with  an  easily -moved  rug. 

The  ideal  kitchen.  —  The  kitchen,  although  it  may 
not  seem  so  important  to  the  average  boy  or  girl,  is  really 
one  of  the  most  important  rooms  in  the  house.  Here 
food  is  prepared,  dishes  are  washed,  food  supplies  stored, 
and  frequently  the  family  washing  done.  This  requires 
a  good  gas  or  coal  range,  a  fireless  cooker,  especially  for 
use  in  hot  weather,  exposed  plumbing,  a  large  sink  and 
stationary  tubs.  It  goes  without  saying  that  mother 
must  have  plenty  of  shelves  in  convenient  places  for  the 
numerous  boxes  and  cans  which  she  needs,  and  there 


THE  BATHROOM 


281 


should  be  several  closets,  one  for  pots  and  pans,  another 
for  stores  of  various  kinds,  and  still  another  cupboard 
with  glass  doors  for  the  storage  of  glass  and  dishes.  The 
icebox  should  not  be  in  the  kitchen,  but  in  a  passageway 
which  leads  outside.  A  small  closet,  or  butler's  pantry 


SELVES  ^SHCLO.|K 


VENT 


Saving  steps  in  the  kitchen.    Which  arrangement  do  you  prefer  ?    (After  Frederick.) 

as  it  is  often  called,  may  connect  the  kitchen  and  the  din- 
ing room. 

The  bathroom.  —  The  bathroom,  though  a  small  room, 
is  surely  very  important.  It  has  been  said  that  "  Cleanli- 
ness is  next  to  godliness  " ;  certainly  cleanliness  is  neces- 
sary for  health.  The  bathroom  should  have  painted  or 
tiled  walls  which  can  easily  be  cleaned.  The  floor  should 
be  tiled  or  covered  with  linoleum,  and  all  equipment, 


282         MAKING  AND  BEAUTIFYING  THE  HOME 

including  the  bathtub,  toilet,  bowl,  and  seat,  should  be  of 
white  enamel  ware,  so  that  they  may  readily  be  cleaned. 
There  should  be  ample  provision  for  clean  towels,  bath 
sponge,  and,  if  possible,  there  should  be  a  shower  bath. 
A  medicine  chest  of  white  enamel  ware  with  glass  shelves 
should  complete  the  equipment  of  the  room. 

Cellar  and  heating  plant.  —  Our  ideal  home  is  a  de- 
tached house  with  a  cellar.  In  the  cellar  there  is  storage 
room  for  vegetables,  canned  goods,  wood,  and  coal.  The 
heating  plant  should  be  of  ample  size  to  heat  the  house  in 
the  severest  weather.  Probably  the  best  of  all  types  of  heat- 
ers is  a  combination  of  hot  water  and  hot  air,  the  hot  water 
pipes  heating  the  rooms  in  distant  parts  of  the  building,  and 
the  hot  air  going  to  the  rooms  directly  over  the  furnace. 

The  ideal  home  is  not  always  possible.  It  is  not  to  be 
expected  that  any  of  us  can  live  up  to  all  of  the  standards 
set  in  the  above  paragraphs.  No  one  of  us  has  the  right 
to  say,  "  What  is  the  use  of  trying  to  have  a  better 
home?"  even  though  we  cannot  live  up  to  the  standard 
set  as  our  ideal.  This  is  not  an  age  of  ideal  living,  but 
we  want  to  make  our  standards  high.  It  is  well  to  re- 
member that  an  ideal  home  life  is  possible  even  when  an 
ideal  house  may  not  be  afforded.  If  one  thinks  about 
these  matters  and  tries  to  improve  them  good  will  come 
from  these  suggestions. 

The  score  card.  —  The  following  score  card  gives  a 
standard  for  checking  up  conditions  in  your  own  homes. 
Some  of  you  will  doubtless  want  to  add  to  or  subtract  from 
the  items  given  here.  If  so,  remember  that  the  class  wants 
the  benefit  of  your  ideas.  So  bring  your  card,  with  its 
changes,  and  put  it  before  the  class  in  an  open  discussion. 
Perhaps  a  much  better  card  than  this  will  result. 


SCORE  CARD 


283 


SCORE  CARD.    MY  HOME 


SCORE 

PER- 

MY  S 

C0«£ 

SCORE 

Total 

The  House 
Type 
Detached  with  garden                                 . 

IO 

Semi-detached  back  yard                       .      (7) 

Apartment  or  flat                 (5) 

Ownership 
Owned   no  mortgage 

IO 

Owned  with  mortgage          (5) 

Rented                    (3) 

Bedrooms 
Windows  (average) 
Two  windows         

IO 

One  window                                                     (6) 

No  window                                          .     .      (o) 

Fittings 
Painted  walls,  no  carpet  or  heavy  hangings, 
iron  bed                                           .... 

IO 

Any  one  item  lackin^      (8) 

Any  two  items  lacking                                   (4) 

Living  Room 
All  items  mentioned  in  paragraph,  page  279     . 
At  least  half  items  including  table,  books,  com- 
fortable chairs  and  couch    (5) 
No  items  given  in  paragraph  on  living  room  (o) 

10 

Dining  Room 
Pleasant   outlook,    suitable    table   and   chairs, 
china  closet  and  dish  closet,  buffet,  room  not 
carpeted,  walls  plain  or  inconspicuous  figure, 
table   light    does   not  shine  in   eyes,   room 
clean  and  tidy        
Half  of  items  above       ...                         (5) 

IO 

None  of  items  above      (o) 

Kitchen 
Well  arranged  to   save  steps,   equipped  with 
sink,  table,  range,   tireless   cooker,    kitchen 
cabinet  or  closed  closet,  hot  and  cold  water, 
floors  and  walls  easily  cleaned      

10 

284        MAKING  AND  BEAUTIFYING  THE  HOME 
SCORE  CARD.    MY  HOME  —  Continued 


SCORE 

PER- 

MY  < 

)CORE 

SCORE 

Total 

Kitchen  —  Continued 
Half  of  items  above                                           (5) 

None  of  items  above      ...          .                (o) 

Bathroom 
Bathtub,  shower,  toilet  and  washboard,  fittings 
of  porcelain  or  white  enamel,  open  plumbing, 
hot  and  cold  water,  mirror  well  lighted,  medi- 
cine cabinet,  room  well  ventilated    .... 
Half  of  items  above                                            (5) 

IO 

No  bathroom   (o) 

Heating  plant 
Heater  for  cellar,  whole  house  except  bedrooms 
warm 

IO 

Stoves    in  all    rooms   except   bedrooms.      Oil 
stoves  for  bedrooms        .                              (5) 

Fireplaces  or  wood  stoves  only                       (2) 

Repair  of  home 
House  new,  first  occupants    .     .    ,    »     .     .     . 
House  new  within  ten  years  (7) 
House  over  fifteen  years  old,  many  previous  oc- 
cupants.    Fair  repair     (5) 
House  over  twenty  years  old.  Badly  run  down  (o) 

IO 



GRAND  TOTAL 

IOO 



Ginn  and  Company. 
Henry  Holt  and  Com- 


REFERENCE  BOOKS 

Allen,  Civics  and  Health,  Chapters  I,  II,  III  (For  teachers). 
Barber,  First  Course  in  General  Science,  Chapters  I,  II,  VI. 

pany. 

Bodmer,  The  Book  of  Wonders  (Story  of  Cement).     Presbrey  Syndicate. 
Broadhurst,  Home  and  Community  flygiene,   Chapter  XIII.     J.  B.  Lippincott 

Company. 

Child,  The  Efficient  Kitchen  (For  teachers).    McBride,  Nast  and  Company 
Clark,  The  Care  of  a  Home  (For  teachers).    The  Macmillan  Company. 


REFERENCE  BOOKS  285 

Clark,  An  Introduction  to  Science,  Chapters  XVIII,  XXIX.  American  Book 
Company. 

Farmers'  Bulletin  461,  U.  S.  Dept.  Agr.     The  Use  of  Concrete  on  the  Farm. 

Farmers'  Bulletin,  474,  U.  S.  Dept.  Agr.     The  Use  of  Paint  on  the  Farm. 

Frederick,  Mrs.  C.,  Household  Engineering.  American  School  of  Household  Eco- 
nomics, Chicago. 

Hunter,  A  Civic  Biology,  Chapters  XXII,  XXIV.     American  Book  Company. 

Morris,  Household  Science  and  Arts.     American  Book  Company. 

Portland  Cement  Association  Booklets  26,  no,  135,  140.  in  West  Washington  St., 
Chicago. 

Standards,  Bureau  of,  Bulletin  70. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  XI.  Houghton 
Mifflin  Company. 

Van  Rensselaer,  Manual  of  Home  Making  (For  teachers  and  project  reading). 
The  Macmillan  Company. 


CHAPTER  XVIII 
PLANNING   THE   HOME    GROUNDS 

Problems.  —  i.  To  learn  how  to  make  the  grounds  at- 
tractive. 

2.  Arrangement  and  color  effect  of  flowers. 

3.  To  learn  how  to  take  care  of  house  plants. 

4.  To  find  cut  what  plants  make  a  good  porch  screen. 

Project    I. — To    BECOME  A  LANDSCAPE    GARDENER    FOR   YOUR 

HOME  OR  FOR  SOME  FRIEND'S  HOME. 

1.  Become  familiar  with  the  ground  plans  of  the  best  kept  places 
in  town. 

2.  Collect  and  study  plans  of  home  grounds  which  show  location 
of  buildings,   paths,   driveways,  trees,  shrubs,  flowers,  garden   and 
play  space. 

3.  Apply  knowledge  to  the  particular  home  grounds  you  desire  to 
improve  and  estimate  cost  of  the  improvements. 

4.  Make  a  report,  giving  your  plans  in  detail. 

Suggested  Projects. 

1.  TO  PLAN,  PLANT,  AND  CARE  FOR  A  FLOWER  GARDEN. 

2.  TO  MAKE  A  STUDY  OF  THE  ORNAMENTAL  SHRUBS  AND  TREES 

FOUND  IN  THE  TOWN  OR  NEIGHBORHOOD. 

3.  TO  PLAN,  PLANT,  AND  CARE  FOR  A  WINDOW  GARDEN. 

Planning  the  ground.  —  A  house  needs  a  setting,  just 
as  a  beautiful  stone  in  a  ring  does.  Many  cozy  and  at- 
tractive homes  are  spoiled  by  the  absence  of  attractive 

286 


PLANNING    THE    GROUND 


287 


A  house  without  trees  or  shrubbery. 

shade  trees,  shrubbery,  and  vines  which  might  easily  be 
grown  around  them.  The  house  in  the  above  picture, 
though  a  fine  one,  suffers  because  it  has  no  attractive  sur- 
roundings. Compare  it  with  the  next  picture.  How  much 
more  attractive  the  second  house  appears,  with  its  well- 
shaded  lawns,  its  shrubbery,  and  its  flower  gardens. 


The  home  grounds  here  are  well  planned. 


288 


PLANNING   THE   HOME   GROUNDS 


The  use  of  trees.  —  Trees  are  useful  as  well  as  orna- 
mental. They  are  the  homes  of  many  birds.  They  serve 
to  break  the  force  of  strong  winds  in  winter,  and  give 
pleasant  and  cooling  shade  in  summer.  Trees  give  oft"  much 

moisture  through  their 
leaves.  According  to 
Ward,  an  oak  may  send 
off  226  times  its  own 
weight  in  water  through 
a  growing  season.  This 
moisture  helps  to  cool 
the  air,  and  makes  a 
more  even  temperature. 
But  trees  should  not  be 
so  abundant  about  the 
house  as  to  shut  out  all 
the  direct  sunlight.  A 
good  arrangement,  if  the 
place  is  a  large  one,  is 
secured  by  groups  of 
trees  which  make  natu- 
ral shady  places  on  the 
grounds,  and  if  the  lot  is  a  small  one,  two  or  three  trees 
will  suffice,  planted  so  that  they  will  not  completely  shade 
the  house  but  will  give  an  agreeable  setting  to  it.  Fruit 
trees  may  be  grown  even  on  city  lots. 

The  use  of  trees  and  shrubs  in  beautifying  our  grounds. 
-Landscape  gardening  has  come  into  the  list  of  pro- 
fessions of  late  years,  and  any  one  of  us  may  become  his 
own  landscape  gardener,  if  a  little  common  sense  as  well 
as  artistic  taste  is  used.  We  shall  see  when  we  come  to 
take  photographs  that  a  picture  to  be  artistic  must  be 


Small  fruit  trees  yield  large  returns. 


THE  USE  OF  TREES  AND  SHRUBS 


289 


Well-planned  home  grounds.  3-4  means  three  plants  of  number  4.  i.  Japanese  bar- 
berry. 2.  Bridal  wreath.  3.  Honeysuckle.  4.  Japanese  rose.  5.  Lilac.  6.  Peony. 
7.  Iris.  8.  Phlox.  9.  Deutzia.  10.  Deciduous  trees.  n.  Evergreen  trees. 
(After  Moore  and  Halligan.) 

H.-WHIT.  CIV.  SCI.  IN  THE  HOME  — - 19 


2QO 


PLANNING  THE  HOME  GROUNDS 


balanced,  that  is,  it  must  have  a  certain  amount  of  light 
and  shadow,  of  prominent  foreground  and  distant  back- 
ground. We  must  in  planning  the  home  grounds  re- 
member that  the  house  is  a  gem  in  the  setting,  and  that  the 
setting  of  trees  and  shrubs  should  make  our  house  look  as 
attractive  as  possible.  The  walk  to  the  house  may  be 
bordered  with  flowers,  tulips,  jonquils,  or  lilies  of  the 
valley  in  the  early  spring,  followed  by  marigolds,  sweet 
Williams,  zinnias,  or  other  old-fashioned  border  flowers 
for  the  summer,  and  finally  asters  or  chrysanthemums 
for  the  fall.  Thus  we  have  a  constant  series  of  bloom  along 
the  walk.  The  grounds  may  be  rendered  still  more  at- 
tractive by  planting  shrubs,  such  as  syringa,  a  beautiful 
white  blooming,  sweet  shrub,  or  weigela,  which  flowers  in 
June  and  July,  with  various  shades  of  red  and  white,  and 


Roses  at  their  best.     Ramblers,  red  and  white. 


the  Japanese  quince.     The  lilac,  which  grows  rapidly  and 
whose  blossoms  are  known  to  us  as  early  flowers,  and, 


THE  USE  OF  TREES    AND    SHRUBS  291 

of  course,  roses,  both  the  climbing  and  bush,  should  be 
planted.     The  hardy  hydrangea  is  perhaps  the  best  shrub 


Climbing  vines  give  privacy. 

for  late  flowering.  When  a  small  tree  is  desired  the 
Japanese  maple  or  the  silver  cut-leaf  birch  will  be  found 
to  be  both  beautiful  and  hardy.  For  large  trees  we  may 
choose  elms  with  their  graceful,  overhanging  branches, 
maples  with  their  splendid  coloring  in  the  fall,  beeches, 
and  birches,  with  a  few  evergreens. 

Nothing  is  more  attractive  than  a  hospitable  porch 
covered  with  climbing  roses  and  honeysuckle,  or  other 
vines,  giving  a  sense  of  privacy  and  coolness.  Vines  are 
easily  planted,  and  there  are  many  quickly  growing  ones, 
such  as  the  moon  flower,  the  climbing  ramblers,  and  the 
scarlet  bean.  One  of  the  pleasantest  porches  imaginable 


2Q2 


PLANNING  THE  HOME   GROUNDS 


is  one  shaded  with  a  fine  grapevine.  .  The  leaves  give  a 
pleasant  coolness,  and  the  purple  fruit  is  a  delight  in 
the  early  autumn.  Training  trees  to  climb  is  very  com- 
mon in  Europe,  but  has  not  been  used  so  much  in  this 
country. 

The  indoor  garden.  —  Not  everybody  can  have  a  house 
with  grounds,  but  it  is  perfectly  possible  for  all  of  us  to 


An  indoor  garden  is  a  joy  in  winter. 

have  a  garden  indoors,  not  the  household  plants  like  bac- 
teria, yeasts,  and  mold  which  may  do  harm,  but  a  window 
box  of  beautiful  green  flowering  plants.  The  dining  room, 
especially  if  it  has  sunlight,  is  a  good  place  for  such  a  pro- 
ject. Shelves  may  be  put  up  in  the  window,  and  on  these, 
oblong  boxes  painted  green,  or  flower  pots,  can  be  used. 
What  cheer  is  brought  to  a  room  by  a  sunny  window  filled 
with  geraniums,  oxalis,  fuchsias,  and  in  the  early  spring, 
lilies  and  tulips !  Why  not  make  a  home  project  of  the 
planting  and  care  of  such  a  garden? 


PLANNING  FOR  PLEASURE 


293 


A  home  vegetable  garden. 

Planting  for  profit.  —  The  World  War  with  its  need  of 
the  conservation  of  food  for  shipment  to  our  allies,  and 
supplies  of  fresh  food  for  the  people  at  home,  brought  out 
as  nothing  else  could  the  value  of  the  home  garden.  War 
gardens  in  this  country  were  estimated  in  1918  to  have 
supplied  nearly  five  hundred  million  dollars'  worth  of  vege- 
tables, this  value  equal  to  about  one  twelfth  of  the  Fourth 
Liberty  Loan.  It  was  found  early  in  1917  that  there  were 
186,000  vacant  lots  in  New  York  City,  and  5000  acres  in 
Minneapolis,  Minnesota,  much  of  which  space  was  avail- 
able for  war  gardens,  and  these  figures  could  doubtless 
be  duplicated  in  cities  from  all  parts  of  the  country. 

A  garden  need  not  be  a  large  one  to  be  profitable.  One 
can  raise  enough  vegetables  for  a  family  of  four  in  a  city 
back  yard  on  a  plot  twenty-five  feet  by  twenty-five  feet. 
It  requires  planning  and  a  knowledge  of  soil  and  other 
conditions,  which  will  be  given  in  the  next  chapter.  In 
connection  with  any  home  garden  we  should  always  plan 


294 


PLANNING  THE  HOME   GROUNDS 


to  have  flowers,  and  in  a  city  back  yard  where  space  is 
limited,  the  climbing  plants  can  be  trained  up  the  side  of 
the  fence.  The  borders  can  be  filled  with  plants  which 
mature  early  and  which  can  be  pulled  up  to  make  a  place 
for  others  later.  A  later  study  of  crop  rotation  and 
combination  of  plants  will  enable  us  to  undertake  this 
project  intelligently. 

Planning  for  pleasure.  —  Every  house  lot  of  any  size 
ought  to  be  planned  for  pleasure  and  for  profit.     We  need 

out-of-door  exercise  in  the 
form  of  games  as  well  as 
in  the  form  bf  work. 
Tether  ball,  Russian  nine- 
pins, volley  ball,  quoits, 
or  basket  ball  will  give 
splendid  exercise  in  a 
limited  amount  of  space, 
as  not  over  50  to  200 
square  feet  are  needed 
for  any  of  the  above- 
mentioned  games.  What 
is  better  than  a  good  ten- 
nis court,  a  croquet  lawn, 
or  to  be  more  scientific,  a 
roque  court?  If  we  have 
a  barn  or  garage  on  the 
place  with  a  flat  wall 
having  no  windows,  we 
can  with  very  little  ex- 
pense and  trouble  make  a 
hand-ball  court.  And  if  there  is  room  inside,  this  can  be 
used  both  winter  and  summer,  giving  us  splendid  exercise. 


Russian  ninepins.  Ball  must  go  around  a 
post  (to  the  left  of  picture  but  not  shown 
here)  before  it  strikes  the  pins.  Score  as 
in  bowling.  -  -  .  , 


SCORE  CARD 


295 


We  should  all  remember  that  the  home  to  be  attractive 
must  be  placed  where  we  can  have  a  good  time,  bring 
our  friends,  and  make  our  yards  the  center  of  a  pleasant 
group  of  young  people.  How  many  boys  who  have  read 
this  chapter  can  now  go  home  and  plan  to  add  in  some 
way  to  their  store  of  attractions,  both  for  themselves  and 
their  friends  ? 

Use  of  the  score  cards.  — We  have  two  score  cards  for  this 
chapter,  one  for  boys  and  girls  who  are  fortunate  enough 
to  have  their  own  ground  to  plan  for  and  those  who  live 
in  communities  that  are  thickly  settled.  In  the  latter  case 
the  community  ought  to  provide  means  of  recreation  and 
health  for  all.  If  your  score  is  not  high,  then  there  is 
something  wrong. 


SCORE  CARD.    MY  HOME  GROUND 


Set 

)RE 

Perfect 
Score 

My 
score 

Grounds  planned  for  beauty  or  utility  .     .     .  •  . 

cr 

Shade  trees  grouped 

tr 

At  least  one  fruit  tree      

r 

Porch  screened  with  climbing  vines        

c 

Well-arranged  flower  beds 

5" 

Flowers  from  spring  until  fall 

5" 

Flowering  and  ornamental  shrubs      .     . 

c 

Outhouses  and  garden  screened  with  trees  and  shrubs    . 
Lawn  attractive  and  well  kept.     Borders  kept  trimmed 
Play  space  with  at  least  one  game  in  use        .     .     . 

s 

5 
5 

TOTAL    

CQ 

The  following  score  card  may  be  used  by  city  children 
or  those  who  do  not  have  home  grounds. 


296 


PLANNING  THE   HOME   GROUNDS 


SCORE  CARDS.    PARKS,  PLAYGROUNDS,  AND  LIBRARIES 


Sc( 

)RE 

Perfect 
Score 

My 

Score 

Public  park  within  half  mile  of  home     
Within  one  mile       .... 

(r) 

IO 

Within  two  miles     

(7) 

Parks  have  ball  fields,  tennis  courts,  and  golf  links 
Two  of  above 

(6) 

10 

One  of  above 

(.) 

Public  playgrounds  'within  quarter  mile  from  home 
Within  half  mile      

*CO 

IO 

Within  one  mile      
Public  baths  within  one  mile  of  home 

(3) 

IO 

Within  two  miles 

(r) 

Within  three  miles       ....          ... 

CO 

Public  library  within  half  mile  of  home      .... 

IO 

Within  three  quarters  mile   
Within  one  mile      .               . 

(5) 
f*) 

TOTAL 

ro 

REFERENCE  BOOKS 

Bailey,  Encyclopedia  of  Agriculture  (Teachers  —  Article  on  planning  use  of  grounds, 
horticulture).  The  Macmillan  Company. 

Hodge,  Civic  Biology,  Chapters  I,  VIII.     Ginn  and  Company. 

Mayne  and  Hatch,  High  School  Agriculture,  Chapter  XIX.  American  Book  Com- 
pany. 

McKeever,  Farm  Boys  and  Girls.    The  Macmillan  Company. 

Moore  and  Halligan,  Plant  Production,  Chapter  XIX.     American  Book  Company. 

Nolan,  The  Teaching  of  Agriculture,  Chapter  IV  (Teacher's  use).  Houghton 
Mifflin  Company. 

Trafton,  Science  of  Home  and  Community.     Houghton  Mifflin  Company. 

Transeau,  Science  of  Plant  Life,  Chapter  I.     World  Book  Company. 

Van  Rensselaer,  Manual  of  Home  Making,  Chapter  I  (Teachers).  The  Macmillan 
Company. 


CHAPTER  XIX 
THE   HOME   GARDEN 

Problems.  —  i.  To  understand  the  nature  of  different 
soils. 

2.  To  learn  the  value  of  water  and  air  in  the  soil. 

3.  What  are  the  purposes  and  methods  of  cultivation? 

4.  To  find  out  what  are  the  important  plant  foods,  and 
how  you  would  supply  them  if  lacking. 

5.  To  learn  how  to  force  early  vegetables. 

Experiments  and  demonstrations.  —  i.  To  test  a  sample  of  garden  soil 
for  acidity  with  blue  litmus. 

2.  To  show  capillarity  in  gravel,  sand,  clay,  and  loam. 

3.  To  show  the  effect  of  cultivation  to  prevent  loss  of  soil  water. 

4.  To  test  the  starch-making  power  of  a  plant  in  sunlight  and  in  absence 
of  light. 

Project  I.  — To  LEARN  WHAT  THE  SOIL  NEEDS  FOR  ANY  PARTICU- 
LAR CROP. 

i.  Does  it  need  humus?  2.  Does  it  need  draining?  3.  Does 
it  need  lime?  4.  What  are  the  three  principal  chemicals  found  in 
commercial  fertilizers?  Which  are  needed  in  my  garden? 

Suggestion. 

A  test  to  show  what  chemical  elements  are  most  needed  is  best 
carried  out  in  plot  testing  as  follows: 

Make  seven  equal-sized  plots,  say,  5  feet  wide  by  25  feet  long. 

297 


298 


THE  HOME   GARDEN 


A  =  i  Ib.  Sodium  Nitrate 
B  =  i  Ib.  Potassium  Sulphate 
C  =  2  Ib.  Acid  Phosphate 

On  plots  i,  4,  and  7,  use  no  fertilizer  whatever;   on  plot  2,  use 
A,  B,  C;  on  3,  use  B  and  C;  on  5,  use  A  and  B;  on  6,  use  A  and  C. 

Plant  same  amount  of  seeds  on  each 
plot;  give  all  same  care.  Compare 
crops  from  each  plot  to  decide  the 
fertilizer  most  needed  by  the  soil  for 
that  particular  crop. 


NO  FERTILIZER 

1 

A,  B  AND  C 

2 

B  AND  C 

3 

NO  FERTILIZER 

4 

A  AND  B 

5 

A  AND  C 

6 

NO  FERTILIZER 

7 

Suggested  Projects. 

1.  TO    PLAN,    PLANT,    AND    TAKE 
CARE  OF  THE  VEGETABLE  GARDEN. 

2.  TO  MAKE  AND  USE  A  HOTBED  OR 
A  COLD  FRAME. 

3.  MAKE  A  COLLECTION  OF  DIF- 
FERENT   TYPES    OF    SOILS    FOUND    IN 

YOUR  NEIGHBORHOOD,  KEEPING   A   RECORD   OF   THE   KIND  OF  VEGETA- 
TION   OR   LACK   OF   PLANT   LIFE   FOUND   IN  EACH   LOCALITY. 

Science  and  the  home  garden.  — "  What  do  I  want 
to  know  about  science  in  taking  care  of  my  home  gar- 
den? "  -  might  be  the  remark  of  a  boy  who  has  had  some 
gardening  experience.  He  has  grown  vegetables  and 
flowers  without  any  more  knowledge  than  the  common 
sense  that  he  has  picked  up  from  older  people  or  read  in 
books  or  garden  magazines.  It  is  true  that  a  person  might 
have  a  flourishing  garden  and  know  very  little  about  the 
scientific  principles  necessary  to  understand  the  soil  and  the 
life  of  the  plants  living  in  it.  But  when  we  consider  that 
plants  are  living  things,  that  they  require  certain  "  plant 
foods  "  or  raw  food  materials,  and  that  they  must  be  pro- 
vided with  what  they  most  require  in  order  to  grow  to  their 


WHAT  IS  SOIL? 


299 


full  size,  then  we  can  at  once  see  the  real  reason  for  know- 
ing some  science.  How  otherwise  could  we  improve  the 
yield  in  our  gardens?  If  we  do  not  know  about  the  com- 
position of  soil,  the  principles  underlying  crop  rotation,  the 
reasons  for  the  use  of  certain  fertilizers,  or  the  different 
ways  of  handling  soil,  then  it  is  not  likely  that  we  shall  get 
as  much  out  of  our  home  garden  as  the  boy  or  girl  who 


Cultivating  the  home  garden. 

does  have  this  knowledge.  The  following  pages  will  help 
us  to  apply  our  knowledge  of  science  to  the  project  of  mak- 
ing our  home  garden  more  productive. 

What  is  soil  ?  —  We  have  already  learned  that  soil  is 
composed  largely  of  inorganic  material,  as  powdered  rock, 
and  that  it  usually  contains  organic  material  which  has 
come  from  the  decay  of  plants  and  animals.  Most  of  us 
say  that  dark  soil  is  rich,  meaning  that  it  has  a  great 
deal  of  organic  material  in  it.  Soils,  as  we  know,  may  be 


300 


THE  HOME   GARDEN 


sandy  or  clayey,  and  thus  we  sometimes  speak  of  them  as 
light  or  heavy ;  a  heavy  soil  holds  water. 

Experiment.  —  To  test  a  sample  of  garden  soil  for  acidity. 

Materials:  Blue  litmus  paper.  Some  acid,  as  hydrochloric  acid,  vinegar, 
or  lemon  juice.  Quicklime. 

Method:  Observe  the  effects  of  acids  upon  blue  litmus  paper  by  wetting 
litmus  paper  with  some  dilute  acid.  Vinegar  or  lemon  juice  may  be 
used.  What  color  change  is  observed  ?  This  is  caused  by  acids.  Wet 
a  sample  of  garden  soil  with  water.  Lay  the  blue  litmus  paper  into 
this,  and  let  it  remain  for  a  short  time.  Examine  to  see  if  there  is  a 
color  change  which  indicates  the  presence  of  an  acid.  If  the  soil  is 
found  to  be  acid,  add  a  small  quantity  of  powdered  lime  and  mix 
thoroughly.  After  twenty-four  hours  test  for  acidity.  What  is  the 
result?  What  is  one  way  of  correcting  acidity  in  the  soil? 

Water  in  the  soil.  —  You  are  all  familiar  with  the  fact 
that  coffee  creeps  up  on  the  lump  of  sugar  placed  partly 
in  it,  and  that  oil  rises  in  the  lamp  wick.  This  rise  of 
fluids  against  the  force  of  gravity  is  called  capillarity. 
Soil,  as  the  diagram  shows,  if  examined  under  a  magnify- 
ing glass  would  be  found  to  be  made  up  of  millions  of  par- 
ticles of  different  sizes,  each  particle  holding  around  it  a 
little  film  of  water.  Water  rises  through  the  spaces  be- 
tween soil  particles  by 
capillary  action,  and 
thus  is  held  in  the  soil 
not  far  from  the  surface. 

Experiment.  —  To  show  capil- 
larity in  gravel,  sand,  clay, 
.   and  loam. 

Materials:    Four  large  glass 
tubes,  or  cylindrical  lamp 
chimneys.       Dry       sand, 
coarse  and  fine.     Dry  powdered  clay.     Dry  loam.     A  rack   to   sup- 


The  soil  particles  are  each  surrounded  by  a  film 
of  water. 


port  the  tubes.     Basin.     Cheesecloth. 


EFFECTS  OF  CULTIVATION  ON  SOIL  301 

Method:  Tie  two  thicknesses  of  cheesecloth  over  the  bottoms  of  the 
tubes.  Fill  the  tubes  respectively  with  coarse  sand,  fine  sand,  clay, 
and  loam.  Support  the  tubes  so  that  their  lower  ends  are  half  an  inch 
above  the  bottom  of  the  basin.  Pour  water  in  the  basin  to  a  depth 
of  one  inch. 

Observation  and  Conclusion:  Compare  these  soils  in  the  rapidity  with  which 
the  water  rises  and  the  height  which  it  finally  reaches.  Which  soil 
can  take  the  water  the  greatest  distance  above  the  water  table? 

Air  in  soil.  —  This  same  loose,  porous  structure  of  the 
soil  allows  a  certain  amount  of  air  to  remain  in  the  spaces. 
Plants  breathe,  and  need  the  oxygen  of  the  air  just  as 
much  as  we  do.  And  since  the  delicate  roots  of  plants 
absorb  air  as  well  as  water,  porosity  of  soil  is  very  necessary 
for  the  garden. 

Experiment.     To  show  the  effect  of  cultivation  in  preventing  loss   of  soil 
water. 

Materials:  A  box  about  8  inches  by  14  inches  by  4  inches,  filled  with 
garden  soil.  Two  glass  tumblers. 

Method:  Let  the  box  with  soil  stay  out  of  doors  until  after  a  good  rain, 
then  bring  it  into  the  house.  The  rain  has  made  the  soil  compact. 
After  the  surface  appears  dry 'rake  the  surface  of  one  half  of  the  box  with 
a  fork  to  loosen  the  surface  soil  particles,  making  a  loose,  dry  mulch. 
Place  one  glass,  mouth  down,  over  the  untouched  surface,  and  the 
other  glass  over  the  raked  surface.  Let  the  box  stand  in  the  sun  for 
an  hour  or  so.  Compare  the  amount  of  water  that  condenses  on  the 
two  glasses  when  they  have  cooled  down  a  little. 

_  Conclusion:   Does  this  experiment  give  you  any  evidence  regarding  the 
method  of  conserving  soil  moisture? 

Effects  of  cultivation  on  soil.  —  In  order  to  keep  the  soil 
broken  up  so  that  it  may  not  become  packed  too  firm 
and  hard,  thus  preventing  water  and  air  from  passing 
readily  through  it,  we  cultivate,  or  break  up  the  top  layer 
of  the  soil  either  by  hoeing,  raking,  harrowing,  or  by  means 
of  a  cultivator.  Cultivation  crumbles  the  soil,  and  allows 
the  plant  roots  to  creep  through  it  more  easily.  It  breaks 


302 


THE  HOME   GARDEN 


up  the  soil  particles  so  that  water  can  soak  out  the  ma- 
terials which  the  plants  use  for  food.     It  allows  the  air  to 


Cultivation  in  the  Central  West. 


pass  through  the  soil,  and  by  making  a  loose  mulch  or 
broken  surface  (see  diagram  below)  water  is  more  easily 
kept  in  the  garden  soil. 


PLOWED    SOIL 


I  NOT-.:  HARROWED 


.SUBSOIL        -MSppp         jalte,' SUBSOIL  «f 

HH I 

A  B 

A,  Soil  as  left  by  the  harrow.    B,  The  same  soil  packed  by  rain.     (After  Mayne 
and  Hatch.) 

Mineral  materials  in  the  soil.  —  While  soils  differ  a  good 
deal   in   their  mineral    content,    there   are   certain  min- 


HOW  PLANTS  TAKE  WATER  OUT  OF  THE   SOIL     303 


AH  food,  elements  -   d  tut      -      eituJtr 


Result  of  test  to  show  need  of  mineral  foods. 


erals  that  must  be  present  in  small  quantities  in  order 
that  plants  may  grow.  Living  matter  is  a  very  com- 
plex substance.  We 
cannot  give  the  exact 
proportion  of  its  ele- 
ments, but  we  know 
that  it  contains  a  large 
portion  of  carbon,  hy- 
drogen, oxygen,  nitro- 
gen, and  a  much  smaller 
portion  of  calcium,  sul- 
phur, potassium,  mag- 
nesium, phosphorus,  so- 
dium, and  chlorine.  It 
would  be  very  easy  to 
show  by  growing  plants 

in  water  containing  solutions  of  these  mineral  materials, 
that  they  will  not  live  if  certain  of  these  ingredients  are 
not  found  in  the  water  which  they  absorb. 

How  our  plants  take  water  out  of  the  soil.  —  If  you 
examine  some  growing  radish  or  mustard  seedlings  you 
find  that  the  roots  of  the  tiny  plants  are  covered  with  a 

fringe  of  white, 
hairlike  structures. 
These  are  called 
root  hairs.  They 
are  long  cells  pro- 
jecting from  the 
sides  of  the  root, 
and  are  the  ab- 
sorbing organs  of 
the  plant.  The 


Diagram  of  a  root  hair :    CS,  cell  sap ;   CW,  cell  wall ; 
P,  protoplasm ;  N,  nucleus ;  S,  particles  of  soil. 


304  THE   HOME   GARDEN 

outer  portions  of  the  roots  of  most  plants  are  provided  with 
these  little  structures,  so  that  water  is  constantly  being  taken 
by  absorption.  Since  plants  pass  off  many  times  their  own 
weight  of  water  by  evaporation  through  their  leaves  during 
the  growing  season,  the  root  hairs  must  have  a  very  con- 
siderable work  to  do.  We  shall  not  try  to  show  now  how 
they  take  the  water  in.  It  is  sufficient  to  know  that  water 
with  its  soluble  mineral  salts  passes  from  these  root  hairs 
up  through  the  roots  and  stems  to  the  leaves  where,  as  we 
shall  see,  it  is  used  in  making  living  matter  and  food  for 
the  plant. 

The  root  hairs  take  more  than  water  out  of  the  soil.  — 
If  a  root  possessing  root  hairs  is  washed  carefully,  it  will  be 
found  to  have  little  particles  of  soil  still  clinging  to  it.  These 
particles  of  soil  seem  to  be  cemented  to  the  sticky  surface 
of  the  root  hair.  Root  hairs  give  off  an  acid.  Sometimes 
soils  become  too  acid.  Lime  added  to  such  soils  helps  to 
neutralize  the  acid  and  make  them  fit  for  garden  use.  Acids 
in  the  soil  help  dissolve  some  of  the  mineral  substances. 
The  resulting  solutions  mixed  with  soil  water  are  absorbed 
by  the  root  hairs.  There  is  also  much  mineral  matter 
from  the  soil  dissolved  in  water  without  the  aid  of  the 
acid,  which  is  taken  up  by  the  root  hairs. 

Plants  take  nitrogen  from  the  soil.  —  One  very  neces- 
sary element  in  the  composition  of  living  matter  is  nitro- 
gen. Nitrogen  makes  up  nearly  four  fifths  of  the  air 
around  us,  and  yet  it  is  not  available  for  use  by  plants 
until  certain  bacteria  In  the  soil  have  acted  on  it.  Some 
of  these  bacteria  live  in  little  nodules  or  lumps  on  the 
roots  of  clovers,  peas,  beans,  and  other  plants  called  le- 
gumes and  have  the  power  in  some  mysterious  way  to  take 
some  of  this  nitrogen  out  of  the  air  and  fix  it  so  that  it 


REASONS  FOR  ROTATION  OF  CROPS 


305 


becomes  usable  in  the  soil  as  plant  food.  Nitrogen  in  the 
bodies  of  dead  plants  and  animals  also  is  acted  upon  by 
the  bacteria  which  cause  decay,  and  is  eventually  made 
into  soluble  mineral  substances  called  nitrates.  The 
changes  through  which 
nitrogen  passes  are  too 
complex  for  us  to  ex- 
plain at  present,  but  we 
should  remember  that 
in  all  the  world  it  is  in 
circulation,  from  the 
bodies  of  living  plants 
and  animals,  to  the  soil, 
there  to  be  changed  into 
soluble  nitrates  which 
may  be  absorbed  by  the 
roots  and  used  by  the 
plants  again. 

Reasons  for  rotation 
of  crops.  —  It  is  com- 
mon knowledge  among 
boys  and  girls  who  have 
had  gardens  that  the  soil 

"  wears  out  "  after  a  while,  and  that  it  becomes  necessary 
either  to  add  manure,  which  contains  nitrogen  in  a  usable 
form,  or  some  artificial  fertilizer  which  contains  nitrates, 
phosphates,  or  potash.  By  raising  peas,  alfalfa,  or  clover, 
we  can  often  bring  back  the  soil  to  its  former  state  of 
fertility.  A  boy  who  wishes  to  get  the  most  out  of  his 
garden  will  rotate  the  crops,  or  make  a  combination  plant- 
ing. This  enables  him  to  get  much  more  out  of  his  garden 
than  if  he  planted  only  one  crop.  A  good  combination  for 

H.-WHIT.   CIV.   SCI.   IN  THE  HOME  —  2O 


306  THE  HOME   GARDEN 

two  crops  in  a  year  would  be  early  peas  followed  by  toma- 
toes, squash,  or  sweet  corn ;  or  radishes,  lettuce,  or  spinach 
followed  by  lima  beans,  string  beans,  or  carrots ;  or  string 
beans  followed  by  celery,  cabbage  set  out  from  plants, 
beets,  or  turnips.  In  which  of  these  plantings  do  we  get 
nitrogen  provided  for  the  soil  ? 

How  plant  food  is  changed  into  living  material  and  food 
for  animals.  —  A  simple  experiment  would  convince  you 
that  certain  garden  vegetables  contain  foods.  If  you  take 
carrots,  peas,  beans,  •  radishes,  turnips,  potatoes,  or  any 
other  vegetables  you  may  choose,  and  test  each  of  them 
for  starch,  for  sugar,  and  for  protein  (see  Chapter  VI),  you 
will  be  able  to  prove  the  presence  of  these  food  materials. 
How  did  they  get  there?  They  were  not  in  the  soil 
and  they  were  not  in  the  seeds  in  large  enough  quanti- 
ties to  make  the  amounts  we  find  when  we  gather  the 
vegetables.  We  know  the  plants  made  them,  but  how? 

Experiment.     To  test  the  starch-making  power  of  a  plant  in  sunlight  and 
in  the  dark. 

Materials:  A  green  plant.     Black  alpaca  cloth.     Wood  alcohol.     Iodine. 

Method:  Place  any  small  green  plant  in  a  dark  room  for  24  hours.  Then 
cover  parts  of  several  different  leaves  with  strips  of  black  cloth.  Ex- 
pose to  direct  sunlight  for  an  hour  or  more.  Pick  the  leaves  which 
were  covered,  take  off  the  cloth,  and  place  the  leaves  in  hot  wood 
alcohol  to  dissolve  the  green  coloring  matter.  When  free  from  green 
color,  wash  the  leaves  and  place  them  in  a  solution  of  iodine  to  test  for 
starch. 

Observation:  What  evidence  do  you  find  in  regard  to  the  presence  of 
starch  in  any  part  of  the  leaf? 

Conclusion:  Why  do  we  place  the  plant  in  the  dark  at  the  beginning  of 
this  experiment?  What  effect  does  sunlight  have  upon  green  leaves? 
How  do  you  know?  What  effect  does  absence  of  light  have? 

The  leaf  a  food  manufactory.  —  This  experiment  shows 
us  that  the  green  leaves  of  plants  act  as  factories,  in  which 


A  HOME   GARDEN   PROJECT 


307 


sunlight  with  its  energy  is  the  power  that  runs  the  factory. 
The  green  coloring  matter  in  the  leaf,  under  the  influence 
of  sunlight,  takes  carbon  dioxide  from  the  air  and  water 
from  the  soil,  and  changes  them  into  sugars  and  starches. 
It  uses  the  mineral  salts  and  carbon  compounds  to  make 
proteins,  and  the  living  matter  from 
which  the  plant  is  formed.  '  Each 
one  of  us,  eating  food  which  plants 
have  formed,  may  make  living 
matter  of  it,  or  if  we  prefer  a  mixed 
diet  of  animal  and  plant  food,  we 
take  the  flesh  of  some  animals 
which  have  lived  upon  food  manu- 
factured by  green  plants.  In 
either  case  the  food  was  originally 
made  by  plants,  hence  food  supply 
ultimately  depends  on  plants  for  its 
source. 

A  home  garden  project.  —  We  know  that  the  soil  must 
be  well  watered,  and  we  know  that  we  need  sunlight  in 
order  to  have  a  successful  garden.  We  therefore  choose 
a  slope  which  faces  south  so  as  to  get  as  much  light  as 
possible,  and  an  area  free  from  trees.  Take  a  square 
ruled  sheet  of  paper ;  five  squares  to  the  inch  is  a  con- 
venient ruling.  Lay  out  the  garden  according  to  the  area 
you  have.  Mark  the  borders  with  green  crayon.  Put  in 
flower  beds,  using  the  colors  of  the  flowers,  also  show  the 
position  of  any  fruit  trees,  or  shade  trees,  grape  vines,  or 
the  like.  Mark  off  your  space  for  vegetables,  putting 
green  or  other  colored  dots  to  show  the  position  of  dif- 
ferent plants.  Use  the  suggestions  in  table  (p.  311)  for  the 
distances  apart  for  planting  your  vegetables.  Make  plans 


Starchless  area  in  a  leaf  caused 
by  excluding  sunlight  by 
means  of  a  strip  of  black 
cloth. 


THE   HOME   GARDEN 


Oxygen 


for  crop  rotation,  using  a  second  sheet  of  paper,  which  may 
be  placed  alongside  of  the  first.  Keep  your  plans  for  future 
work  in  the  garden.  Such  plans  could  be  made  in  early 
spring  or  in  the  winter,  and  would  help  greatly  when  you 

come  to  work  the 
ground.  Keep  a  record 
of  the  approximate  dates 
of  planting  the  differ- 
ent vegetables,  and  the 
number  of  rows  or  hills 
to  be  planted.  Later, 
when  vacation  comes, 
and  you  are  planting 
your  garden,  you  will 
be  surprised  to  see  how 
useful  these  directions 
are. 

Use  of  the  cold  frame 
and  the  hotbed.  —  An 
excellent  home  project 
would  be  the  construc- 
tion of  a  hotbed  or  cold 
frame.  Cold  frames  en- 
able us  to  get  a  much 
longer  period  for  grow- 
ing vegetables.  In  the 
early  spring  they  are 
especially  useful  to  raise  parsley,  lettuce,  and  radishes  for  the 
table.  They  also  give  tender  plants  as  tomatoes  and  pep- 
pers protection  from  the  cold.  A  cold  frame  could  easily  be 
manufactured  by  taking  an  old  storm  window  or  any 
small  window  as  a  top,  and  fitting  it  over  a  frame  made 


*„&  A  typical  leaf 
SF  r~  'cell  producing 
VstarcK(CH(5), 
/rom  the  elements 
/  HOandCO 


Carbon  dioxide/rom 
tTie  air  reaches  cells 
througH  lower  surface, 
A  cfiv^d7 


va 

J  bundles 
gives  th 
element: 
H,0. 


Water  tctloe-rx 
lay  root, 


matter  also 
"by 


Diagram  to  illustrate  the  formation  of  starch  in 
a  leaf. 


USE  OF  THE  COLD  FRAME  AND  THE  HOTBED     309 


of  boards  nailed  together  to  form  a  rectangle.  The  frame 
is  simply  a  box  without  a  bottom,  set  into  the  ground. 
Prepare  the  soil  in  this  box  with  special  care,  using  manure, 


ENERGY  FROM  SUN 

\  1  / 


ENERGY  SEt  FREE  AS  HEAT 


THESE-  TEAR-  LOwjN»AMMOniA 
MPLEX  ORGANIC  SU 
TANCES  AND  SET  F&E 


AMMON1A|E>UII'I> 

(NI^)>  |OR<^ANIC  SUBSTA 


(H20) 


(H20) 


CA15BO 

(C02) 


CARBON  DIOXIDE 
(CO*) 


The  relation  between  green  plants  and  animals. 

and  breaking  the  soil  up  into  fine  particles.  Seeds  planted 
under  glass  will  grow  rapidly  because  of  the  heat  which 
is  retained  by  it,  and  if  the  frames  are  covered  up  with 


Cold  frame. 


thick  cloths  or  blankets  at  night,  plants  may  begin  to 
grow  two  months  earlier  in  the  spring  and  continue  two 
months  later  in  the  fall.  The  hotbed  is  a  deeper  box  hav- 


310  THE   HOME   GARDEN 

ing  a  bed  three  feet  deep.  The  lower  part  is  filled  with 
manure,  which  is  allowed  to  heat  and  then  is  reopened, 
being  tested  from  day  to  day  until  it  comes  to  a  tempera- 
ture of  eighty  degrees  Fahrenheit.  Cucumbers,  lettuce, 
muskmelons,  and  tomatoes  may  be  started  in  the  hotbed, 
and  later  transferred  to  the  outside.  To  have  the  hot- 
bed work  successfully,  it  should  be  banked  on  the  outside 


Cross  section  of  a  hotbed.     (After  Moore  and  Halligan.) 

with  manure  in  order  to  keep  the  heat  in,  and  remember 
to  cover  it  at  night  in  cold  weather  with  old  rugs  or  mats 
in  addition  to  the  sash.  The  table  on  the  next  page 
gives  some  useful  information  for  planting  your  own 
garden. 

Score  card  of  my  home  garden.  —  It  is  not  in  the  coun- 
try alone  that  school  gardens  nourish.  Very  many  city 
boys  and  girls  have  an  opportunity  to.  compete  with  coun- 
try boys  and  girls  in  the  home  garden  project.  It  will 
interest  you  all  to  know  that  if  you  score  high  in  this  project 
you  ought  to  belong  to  the  United  States  School  Garden 
Army.  Perhaps  you  do  —  and  perhaps  you  have  already 
received  an  award  from  them.  If  not,  why  not  try  for  it 
next  summer  ?  The  note  found  under  the  title  of  the  score 
card  will  give  you  the  address  to  which  you  may  write 
for  directions. 


SCORE  CARD  OF  MY  HOME  GARDEN 


PLANTING  AND  SEED   TABLE  FOR  VEGETABLES  FOR  THE  HOME 
GARDEN 

From  Bulletin,  "The  Home  Vegetable  Garden."  by  C.  W.  Waid,  Michigan  Agricultural 

College. 


NAME  OF 
VEGETABLE 

DATE  OF 
PLANTING 

H  ° 

w  M 
P 

<  ° 

H 
PO 

DISTANCE 
APART 
OF  Rows 

(inches) 

DISTANCE  APART 
OF  PLANTS  IN 
Rows 
(inches) 

O  &*~' 

^ 

45-65 
50-80 
60-85 
95-120 
90-105 

100-150 
75-no 
100-130 
120-130 
130-150 

65-90 

60-80 
150-160 
90-130 

90-120 
60-80 
60-90 
120-150 

25-50 
130-150 
90-120 
125-160 
40-80 

65-90 
100-140 
80-100 
100-140 
100-140 

30-40- 
35-50 
75-100 

!  20-1  80 

30-60 

60-125 
120-130 
100-140 
60-80 
100-150 

>  Seeds, 
first  crop 

2  Plants, 
first  crop 

Hand  culti- 
vation 

Hills 

Drills 

Beans,  bush    .     . 
Beans,  pole      .     . 
Beets      .... 
Brussels  sprouts  . 
Cabbage,  early     . 

Cabbage,  late 
Carrots  .... 
Cauliflower      .     . 
Celery,  early   .     . 
Celery,  late      .     . 

Corn,  early      .     . 
Corn,  late  .     .     . 
Cucumbers      .     . 
Eggplant     .     .     . 
Endive  .... 

Kale       .... 
Kohl-rabi    .     .     . 
Lettuce       .     .     . 
Muskmelon     .     . 
Okra      .... 

Onion,  sets      .     . 
Onion,  seeds    .     . 
Parsley  .... 
Parsnips      .     .     . 
Peas,  early       .     .  . 

Peas,  late    .     .     . 
Peppers       .     .     . 
Potatoes,  early     . 
Potatoes,  late 
Pumpkins  .     .     . 

Radishes,  early    . 
Radishes,  medium 
Rutabaga    .     .     . 
Salsify    .... 
Spinach       .     .     . 

Squash   .... 
Sweet  potatoes     . 
Tomatoes    .     .     . 
Turnips       .     .     . 
Watermelons  .     . 

'May  
'May  15-31 
'April  15-30 
2May  
2  April  15-30 

2May  
'May  

2  April  15-30 

1-2 
1-2 
4-f 

"i:i" 

F 

1-2 
1-2 

B 

24-3 

£i 

2f-3 
24-5 
3-5 

24-3 

4-6 

sR 
4-6 

t-l 
£ 

24-3 
2|-3 

24-3 

6-ic 

IB 

.g 

2  6-  8 

18-30 
24-36 
18-24 
18-30 
18-30 

18-30 
18-24 
18-30 
18-30 
18-60 

24-36 
24-36 
48-60 
24-36 
12-18 

18-30 
18-30 

12-18 

48-60 

18-30 

12-18 
12-18 
12-18 

18-24 
18-30 

24-36 
18-30 
18-30 
24-30 
72-96 

12-18 

12-18 
18-24 
18-24 
18-24 

36-96 

24-36 
24-36 
18-24 

60—72 

8-12 
18-30 

£ 

2-3 

18-24 
12-18 

18-24 

3-4 

"W 

8-10 

IO-I2 

12-18 
12-18 

8-15 
6-8 

4-12 

1  2-1  8 

.PI 

6-10 

3^4 
Drilled 

Drilled 

18-24 

18-24 
24-36 
48-60 
24-36 

12-18 

"48-60" 
18-30 

'May     1-15 
'May  15-31 
'May  15-31 
2May  20-31 
2April  20-30 

'May 

2May     1-15 
1  April  15-30 
'May  15-31 
2May  15-31 

1  April  15-30 
'May  
'April  15-30 
'May  
'April  15-30 

'May     1-15 
2May  15-31 
'April  15-30 
'May  
'May  15-31 

'April  15-30 
'May  
'April  15-30 
'May     1-15 
'April  15-30 

'May  15-31 
2May  15-31 
2May  15-31 
'Anril  15-30 
'May  15-31 

15-18 
9-15 

I  2-1  8 

72-96 

2-3 

1 

w 

Drilled 
Drilled 
6-10 
3-4 
4-6 

14-18 

36-84 
18-36'  ' 

60-72 

3I2 


THE  HOME   GARDEN 
SCORE  CARD.    MY  HOME  GARDEN 


SCORE 


Perfect 
Score 


My 
Score 


General  appearance  2 

Arrangements  of  rows 3 

Freedom  from  weeds 3 

Cultivation  and  care 2 

Choice  of  vegetables 

For  home  use 5 

For  canning 5 

Freedom  from  pests 

Spraying  for  insects  or  disease  when  needed    ....  5 

Other  remedial  measures  if  needed     .......  5 

Evidences  of 

Continuous  cultivation     .  -.    .    .    .    .    .    .    .    .     .  3 

Crop  rotation 'y       . ,  .    .    .    .  2 

Care  of  tools      

Value  of  produce 

Used  at  home 4 

Sold  in  the  market .     .     .  2 

Used  for  canning 2 

Accuracy  of  garden  records 2 

TOTAL 50 


REFERENCE   BOOKS 

Duncan,  Home  Vegetables  and  Home  Fruits  (For  garden  project).     Charles  Scribner's 

Sons. 
Corbett,  The  School  Garden,  U.  S.  Dept.  Agriculture,  Bulletin  218,  also  Farmers' 

Bulletins  154,  255,  408. 
Garden  Manual,  U.  S.   School   Garden   Army,  Bureau  of  Education,  Washington, 

D.  C. 
Food  Supply  in  Families  of  Limited  Means.     League  for  Preventive  Work,  Boston, 

1917. 

1  Modified  from  General  Leaflet  No.  10,  United  States  School  Garden  Army, 
Bureau  of  Education,  Washington,  D.  C. 


REFERENCE  BOOKS  313 

Hunter,  A  Civic  Biology,  Chapters  VI,  VII.     American  Book  Company. 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapters  VI,  VII.     American  Book 

Company. 
Jackson  and  Daugherty,  Agriculture  through  Laboratory  and  School  Gardens.     Orange 

Judd  Company,  N.  Y. 

King,  The  Soil  (For  teachers).     The  Macmillan  Company. 
Lyon,  Soils  and  Fertilizers  (For  teachers).     The  Macmillan  Company. 
Mayne  and  Hatch,  High  School  Agriculture,  Chapter  II.     American  Book  Company. 
Moore  and  Halligan,  Plant  Production,  Chapter  XIII.     American  Book  Company. 
Rexford,  The  ABC  of  Gardening  (Flower  gardens).     Harper  and  Brothers. 
Spellman,  Farm  Science,  Chapter  IV.     World  Book  Company. 
Trafton,  Science  of  Home  and  Community.     The  Macmillan  Company. 
Transeau,  Science  of  Plant  Life,  Chapter  IV.     World  Book  Company. 
The  Small  Vegetable  Garden,  U.  S.  Dept.  Agriculture,  Farmers'  Bulletin  818. 
U.  S.  Food  Administration,  Food  and  the  War,  Chapter  XIII.     Houghton  Mifflin 

Company. 
War  Garden  and  the  Storage  of  Vegetables,  Victory  Edition  1919.     National  War 

Garden  Committee,  Washington,  D.  C. 


CHAPTER  XX 
PLANT   FRIENDS   AND   PLANT   PESTS 

.    Problems.  —  i.    To  learn  something  about  the  work  of 
microorganisms  in  the  soil. 

2.  To  discover  how  fungi  injure  plants. 

3.  To  know  the  life  history  of  common  insect  pests. 

4.  To  find  out  something  of  the  value  of  birds  to  our  gar- 
dens. 

5.  To  learn  how  to  safeguard  the  garden  against  ravages 
of  pests. 

Experiments  and  demonstrations.  —  i.   To  show  the  life  history  of  a 
moth  and  a  butterfly. 

2.  To  learn  to  recognize  insects  that  frequent  flowering  or  garden  plants. 

3.  To  illustrate  the  proper  way  of  making  some  insecticides,  fungicides, 
and  sprays. 

Project  I. — To  ELIMINATE  THE  PLANT  PESTS  FROM  MY  HOME 
GROUNDS. 

1.  Learn  the  habits  and  something  of  the  life  history  of  the  pests 
which  appear. 

2.  Learn  what  pests  are  most  likely  to  attack  each  kind  of  plant 
on  the  grounds. 

3.  Learn  when  to  apply  sprays  most  effectively  and  about  other 
devices  that  may  be  used  to  prevent  or  destroy  the  pests. 

4.  Learn  how  to  prepare  and  to  apply  the  sprays,  etc. 

5.  Report  all  your  efforts  in  fighting  plant  pests  through  an  en- 
tire summer,  showing  to  what  extent  your  garden  benefited. 


THE  LIVING  THINGS  IN  THE  SOIL 


315 


Suggested  Projects. 

1.  TO  ATTRACT  AND  PROTECT  HELPFUL  BIRDS. 

2.  TO  MAKE  A  COLLECTION  OF  INSECTS  AND  CLASSIFY  THEM,  MAK- 
ING  AT   LEAST  ONE   EXHIBIT   FROM  EACH  OF   THE  IMPORTANT  ORDERS. 

The  living  things  in  the  soil.  —  Life  in  this  world  con- 
sists of  a  great  deal  of  give  and  take.  We  could  not  get 
along  comfortably 
at  home  without 
giving  in  to  our 
brothers  and  sis- 
ters, and  without 
helping  mother  and 
father,  for  we  take 
so  much  in  return 
from  them.  In  the 
plant  and  animal 
world  similar  con- 
di tions  exist. 
Plants  could  not 
get  along  without 
dead  organic  mat- 
ter. We  have  seen 
the  need  of  man- 
ure and  other  de- 
cayed materials. 
Garden  soil  must  be  thought  of  as  a  place  where  mil- 
lions of  bacteria  and  other  plants  and  animals  live,  some 
friendly  and  some  unfriendly  to  the  plants  which  are  de- 
sired in  the  garden.  If  we  were  to  examine  soil  for  the 
presence  of  bacteria,  we  would  find  many  more  in  rich 
soil  -than  in  sandy  soil,  and  very  many  more  near  the  sur- 
face than  a  little  distance  farther  in  the  ground.  Most 


This  shows  how  organic  matter  is  broken  down  by  bac- 
teria so  it  may  be  used  again  by  green  plants. 


3i6 


PLANT  FRIENDS  AND   PLANT  PESTS 


bacteria  are  found  within  six  inches  of  the  surface.  An 
examination  of  sandy  soil  has  shown  something  like  100,000 
bacteria  to  the  gram ;  in  the  soil  of  an  ordinary  garden, 
1,500,000  to  the  gram,  while  in  the  soil  surrounding  privies 
and  cesspools,  as  many  as  115,000,000  to  the  gram  may  be 
found. 

Bacteria  in  the  soil  break  down  organic  material,  such 
as  dead  bodies  of  plants  and  animals,  and  help  to  oxidize  it. 

Some  nitrifying  bacteria 
act  upon  ammonia  (a 
product  formed  in  de- 
caying) and  change  it 
to  nitrites,  while  others 
change  these  nitrites  to 
nitrates,  which  can  be 
used  by  plants.  Still 
other  bacteria,  as  we 
have  seen,  are  found  liv- 
ing upon  the  roots  of 
certain  plants,  such  as 

The  nitrogen  cycle.    Follow  the  arrows  and  find     clovers,  peas,  and  beans, 
out  what  becomes  of  the  nitrogen.  .   .. 

Sometimes  a  good  farmer 

buys  these  bacteria  and  puts  them  into  the  soil,  or  inocu- 
lates his  soil.  These  bacteria,  although  they  live  at  the 
expense  of  the  plants  to  which  they  attach  themselves  in 
little  nodules,  yet  take  the  nitrogen  out  of  the  air  which 
is  held  in  the  soil,  and  change  it  into  a  form  that  can  be 
used  by  the  plants.  In  the  end  the  bacteria  have  reduced 
nitrogenous  substances  to  a  soluble  form  which  can  be 
absorbed  through  the  roots-.  There  are  many  other  kinds 
of  bacteria  present  in  the  soil,  —  some  useful,  and  some 
harmful.  The  denitrifying  bacteria  which  are  commonly 


U 1  Jrii^K    1-lAKiY.i £  U.L    Jf JLAXN  1  & 


3*7 


Inocul 


en  fixing  bacteria, 
lligan). 


found  in  acid  soils  release  the  nitrogen  in  the  soil  to 
the  air.  Are  these  useful  or  harmful?  Why?  In  some 
soils,  a  little  one- 
celled  animal  is 
found  which  feeds 
upon  useful  bac- 
teria, thus  de- 
stroying the  fer- 
tility of  the  soil. 
Many  insects  in 
the  larval  or  pu- 
pal form  (page 
134)  make  their  homes  in  the  earth,  and  sometimes  do  much 
harm  by  eating  the  roots  of  plants.  Earthworms,  however, 
are  useful  animals  in  the  garden,  for  they  plow  up  the 

ground  by  boring  their  holes,  thus 
passing  much  soil  to  the  surface  of 
the  garden  through  their  bodies. 
This  loosens  the  compact  soil 
and  allows  water  to  make  its  way 
through  the  ground.  Sometimes 
we  find  moles  and  other  boring 
animals  which  do  harm. 

Other  harmful  plants.  — While 
green  plants  make  food  for  them- 
selves, and  for  the  world  about 
them,  other  little  plants  do  a  great 
deal  of  harm.  Some  of  these  are 
called  fungi.  Among  them  are 

Corn  smut.  Black  knot.  *        6 

(After  Mayne  and  Hatch.)  molds,    TUStS,    Smuts,    SCabs,    and 

many  other  plant  diseases.     We  find,  for  example,  rust  on 
asparagus,  beans,  and  some  other  plants*    Black  rot  is  an- 


PLANT    FRIENDS   AND    PLANT    p] 


other  plant  enemy  which  grows  upon  beets  and  cabbages. 
Blights  are  formed  on  celery,  cucumbers,  and  tomatoes, 
and  other  garden  vegetables.  Still  another  serious  plant 
enemy  is  the  scab  of  potato.  All  these  fungi  live  at  the 

expense  of  various  £ 
plants,  and  make  them 
wilt,  or  the  leaves  curl 
up,  or  some  other  symp- 
tom of  disease  occurs 
This  book  does  not  teL 
you  exactly  how  to 
distinguish  the  various 
plant  diseases.  That 
should  be  a  home  proj- 
ect of  your  own,  and 
there  are  many  excellent 
pamphlets  published  by 
your  state  or  the  Department  of  Agriculture  to  which  you 
can  refer.  For  all  of  these  fungous  diseases,  a  very  excellent 
cure  is  Bordeaux  mixture,  which  is  best  applied  in  a  spray. 
Light  in  relation  to  fungous  growth.  — We  must  remem- 
ber that  fungi  do  not  like  light,  and  therefore  the  garden 
which  is  very  well  shaded  and  too  moist  makes  a  favora- 
ble place  for  them  to  grow.  We  should  never  have  trees, 
or  many  bushes,  planted  around  our  garden,  for  not  only 
do  these  larger  plants  take  a  great  deal  of  "  plant  food  " 
from  the  soil,  but  they  may  do  considerable  harm  also 
by  shading  young  growing  plants. 

Insect  pests.  —  Everybody  who  has  had  a  garden  of  his 
own  knows  that  sooner  or  later  he  must  expect  to  find 
insects  doing  damage  there.  The  insect  damage  to  all 
kinds  of  living  trees  and  plants  in  the  United  States  in  a 


Sample*  of  Bordeaux  mixture.    Two  and 
•bow  Btde  ttUtiftc  and  are  the  beat. 


now  TO  msTiNdUisii  INSISTS 


319 


single  year  is  cst  im;itcd  ;il  one  billion  dollars.  Since  we 
must  expect  insect  pests  the  best  way  to  prevent  damage 
is  to  watch  for  them,  and  to  get  rid  of  them  before 
they  become  numerous.  If  we  remember  that  most  in- 
sects lay  their  eggs  on  the  plants  which  will  later  become 
their  food,  we  can  be  on  the  watch  for  their  eggs,  and  re- 
move them  before  harm  is  done. 
del  the  habit,  of  looking  for 
pests  while  weeding  and  culti- 
vating your  garden.  The  to- 
mato "  worm,"  for  example, 
usually  appears  singly,  and  if 
picked  off  early  a  great  deal  of 
damage  will  be  prevented. 

How  to  tell  an  insect.  —  We 
are  all  familiar  with  insects,  yet 
how  many  boys  and  girls  can  tell 
exactly  how  to  distinguish  them 
from  other  animals  ?  If  we  study 
the  diagram  of  a  bee  shown 
here,  we  find  that  its  body  has 
three  parts,  the  head,  the  middle 
pdrtion  or  the  thorax,  and  the  hind  portion  called  the  ab- 
domen. The  insect  has  six  jointed  legs  and  may  or  may 
not  have  wings.  By  the  above  characteristics  you  can  al- 
ways distinguish  an  insect  from  other  animals. 

Experiment.  —  To  itudy  the  life  history  of  a  moth  and  a  butterfly. 

a.  Eggs 

Method  and  Observations:  In  the  field  look  on  the  under  side  of  leaves 
for  tiny  ovoid  structural  (eggs)  of  moths  and  butterflies.    The  eggs 
of  the  cabbage  butterfly  may  be  found  at  almost  any  time  on  the  under 
side  of  cabbage  leaves. 
Conclusion:  Why  are  the  eggs  laid  on  the  wider  aide  of  certain  leaves? 


ab. 


An  iniect  viewed  from  the  tide. 
Notice  the  head,  thorax,  and  ab- 
domen. What  other  characters 
do  you  find  ? 


320  PLANT   FRIENDS   AND   PLANT   PESTS 

b.  Larva  or  Caterpillar 

Observations:  Note  that,  besides  true  jointed  legs,  the  caterpillar  has 
others  called  prolegs.  How  many  true  legs  are  there  and  where  are 
they  located?  How  many  prolegs  are  there?  Locate  the  spiracles 
or  breathing  holes.  Remember  where  they  are  located  on  an  adult 
insect.  Watch  the  caterpillar  when  it  feeds.  What  kind  of  mouth 
parts  does  it  have?  Might  it  do  damage  to  plants?  How?  * 

Conclusion:  i.  Is  a  caterpillar  a  worm?  (Look  in  a  biology  for  the 
characteristics  of  worms.)  2.  How  might  the  larvae  of  moths  or 
butterflies  be  of  economic  importance  ? 

c.  Pupa 

Materials:  Cocoons  of  several  species  of  moths  with  twigs  or  other  parts 
attached  should  be  furnished  for  this  exercise. 

Note  :   Moths  spin  a  cocoon  for  themselves  at  this  stage.     Butter- 
flies spin  no  cocoon  but  form  a  chrysalis. 

Observations:  Where  do  you  find  the  cocoon  or  chrysalis?  Of  what  dees 
the  cocoon  seem  to  be  composed?  (The  cocoon  of  the  Cecropia  is 
excellent  for  this  purpose.)  In  a  chrysalis  locate  by  means  of  the  body 
markings  the  head,  antennae  or  feelers,  eyes,  wings,  legs,  and  spiracles. 
Are  all  the  parts  of  an  adult  present  ? 

Open  a  cocoon.     What  do  you  find  inside  ?     How  do  you  explain  this  ? 

Conclusion:  Making  use  of  all  the  knowledge  you  have  gained,  write  a 
brief  description  of  the  pupal  stage  of  an  insect  and  tell  of  what  use 
this  stage  might  be  to  the  insect.  Remember  where  you  find  these 
stages. 

d.  Adult  or  Imago 

Method:   Examine  carefully  an  adult  butterfly  or  moth. 

Observations:  How  many  body  regions  has  it?  How  many  legs? 
Wings  ?  Antennae  ?  How  does  this  stage  differ  from  the  pupal  stage  ? 
Note :  All  the  changes  undergone  by  an  animal  from  the  time  it 
leaves  the  egg  to  the  time  it  becomes  an  adult  are  known  as  the 
metamorphosis  of  that  animal.  If  no  great  changes  in  form  occur, 
the  animal  is  said  to  have  an  incomplete  or  direct  metamorphosis. 
But  if  changes  in  form  such  as  in  the  butterfly  or  moth  occur,  the 
animal  is  said  to  pass  through  a  complete  or  indirect  metamorphosis. 

Conclusion:  i.  What  insects  that  you  have  studied  pass  through  a  direct 
metamorphosis?  An  indirect'  metamorphosis?  2.  If  time  permits, 
drawings  might  be  made  to  illustrate  the  life  history  (metamorphosis) 
of  a  moth  or  a  butterfly. 


LIFE  HISTORY  OF  INSECTS 


321 


Life  history  of  insects.  —  If  we  should  watch  the  life 
of  an  animal  from  the  egg  to  the  time  it  develops  into  an 
adult  and  dies  we  would  see  its  life  history.  There  is  a 
great  similarity  in  the  life  history  of  those  insects  which  pass 
through  a  com- 
plete metamor- 
phosis. They 
have  four  stages. 
The  egg  is  the 
first  stage,  often 
laid  on  a  plant 
upon  which  the 
young  insect  will 
feed.  This  stage 
is  followed  by 
one  known  as 
the  larval  stage, 
during  which  the 
animal  feeds  and 
grows  rapidly. 
Familiar  exam- 
ples of  the  larvae 
are  the  caterpil- 

i  u  » 

lars  Or      WOrmS 

we  see  eating 
our  garden  vegetables,  or  the  maggots  we  see  in  decay- 
ing meat.  After  the  larva  has  eaten  and  grown  larger, 
shedding  its  skin  several  times,  it  settles  down,  and  if  a 
moth,  spins  a  cocoon,  and  becomes  quiet  for  a  period. 
This  is  known  as  the  pupal  stage.  Finally  the  adult  in- 
sect breaks  out  from  the  pupa,  and  lives  a  relatively 
short  life,  cluring  which  its  eggs  are  laid,  and  the  life  his- 

H.-WHIT.   CIV.   SCI.   IN   THE  HOME  —  21 


Monarch  butterfly:  adults,  larva,  and  pupa  on  their  food 
plant,  the  milkweed.  (From  a  photograph  loaned  by  the 
American  Museum  of  Natural  History.) 


322  PLANT  FRIENDS  AND   PLANT  PESTS 

tory  or  cycle  begins  over  again.  Much  harm  is  done  in 
our  gardens  by  insects  in  the  larval  stage,  as,  for  exam- 
ple, caterpillars,  cutworms,  wireworms,  and  the  like.  A 
great  many  insects,  in  the  adult  stage,  however,  do  dam- 
age by  sucking  juices  from  plants.  These  are  bugs,  and 
are  known  by  their  long  sucking  beaks.  The  seventeen- 
year  locust  or  common  cicada,  and  the  squash  bug,  are 
good  examples.  Still  other  adult  insects  such  as  the 
locusts,  commonly  called  grasshoppers,  do  much  harm  by 
chewing  grass  or  vegetables  which  make  up  their  food. 

Collecting  insects.  —  A  very  interesting  and  profitable 
pastime  is  the  collection  and  identification  of  different 
kinds  of  insects.  It  is  very  easy  to  get  an  equipment 
necessary  to  collect  them.  A  few  cigar  boxes,  pieces  of 
flat  cork,  insect  pins,  a  cyanide  bottle,1  and  a  collecting 
net  are  all  of  the  implements  necessary.  Insects  are  di- 
vided by  scientists  into  orders,  or  groups,  which  have  cer- 
tain characteristics  in  common.  There  are  nineteen  orders, 
but  only  five  or  six  are  very  common,  and  these  are 
quite  easily  learned.  Study  any  good  elementary  biology, 
and  you  will  soon  be  able  to  distinguish  the  chief  orders. 
For  our  purposes  it  is  enough  for  us  to  know  the  insects 
which  do  harm  in  our  gardens  by  chewing,  and  the  insects 
which  do  harm  by  sucking. 

Experiment.     To  learn  to   recognize  insects  that  frequent   flowering   or 

garden  plants. 
Method:  This  work  may  best  be  taken  on  a  field  trip. 

Note :  Insects  have  been  shown  to  be  animals  that  have  three 

1  A  cyanide  bottle  is  made  by  taking  a  wide-mouth  bottle  or  a  fruit 
jar,  placing  in  it  a  small  piece  of  cyanide  of  potassium,  and  covering  this 
quickly  with  soft  plaster  of  Paris.  The  cyanide  is  deadly  poison.  The 
fumes  are  sufficient  to  make  you  sick,  so  a  cyanide  bottle  is  best  prepared 
by  some  older  person,  and  should  be  handled  with  great  care. 


COLLECTING  INSECTS  323 

parts  to  the  body,  three  pairs  of  jointed  legs,  feelers,  compound  eyes, 
and  a  more  or  less  hard  skeleton  on  the  outside  of  the  body.  They 
may  or  may  not  have  wings.  They  breathe  through  a  system  of  air 
tubes  called  tracheae. 

The  following  orders  or  groups  of  insects  are  likely  to  be  found  feeding  or 
living  upon  flowering  plants.  The  position  arid  kind  of  wings  and  the 
kind  of  mouth  parts  are  the  guides  by  which  we  know  the  orders  of  insects. 

Bees  and  Wasps  (Hymenoptera,  membrane  wings).  —  The  wings  are 
gauzy  and  four  in  number.  These  insects  have  stings  (look  at  the  end 
of  the  abdomen). 

Butterflies  and  Moths  (Lepidoptera,  scale  wings).  —  Characterized 
by  having  two  pairs  of  large  wings,  covered  with  tiny  bright-colored 
scales.  Head  provided  with  a  long  proboscis  or  sucking  tube  which  is 
coiled  up  when  at  rest. 

Grasshoppers  (Orthoptera,  straight  wings).  —  Found  on  most  green  weeds 
or  garden  plants.  The  mouth  parts  are  fitted  for  biting.  Hind  wings, 
if  present,  are  folded  up  lengthwise  under  the  outer  wings  when  at  rest. 

Flies  (Diptera,  two  wings).  —  Usually  small  insects  with  but  a  single  pair 
of  gauzy  wings.  A  short  proboscis.  Not  plant  feeders. 

Bugs  (Hemiptera,  half  wings).  —  A  jointed  proboscis  which  points 
backwards  is  the  only  sure  mark  of  this  group. 

Beetles  (Coleoptera,  sheath  wings).  —  Characterized  by  having  a  strong 
front  pair  of  wings  called  elytra,  usually  covering  the  hind  wings  and 
always  meeting  in  a  straight  line  down  the  middle  of  the  back.  Mouth 
parts  hard,  pincher-like  jaws. 

a.  Field  Work 

Method:  Collect  as  many  different  kinds  of  insects  as  you  can,  making 
careful  notes  as  to  the  locality  where  the  insect  was  found,  the  flowers 
which  it  frequents,  the  kind  of  food  it  was  taking  from  the  flower,  and 
the  order  to  which  it  belongs. 

b.  Laboratory  Work 

Observations:  From  boxes  containing  different  kinds  of  insects  pick  out 
one  from  each  order  given  above  and  give  your  reasons  for  placing 
that  particular  insect  in  the  order  which  you  have  chosen  for  it. 

Conclusion:  i.  Why  do  certain  insects  always  frequent  certain  flowers? 
Look  at  the  insect,  especially  the  mouth  parts,  very  carefully  and 
study  the  form  of  the  flower  before  making  your  decision.  2.  How 
would  you  pick  out  (a)  bee,  (b)  butterfly,  (c)  a  bug,  (d)  grasshopper 
from  the  above  insects? 


324  PLANT   FRIENDS   AND   PLANT  PESTS 


c  f 

a,  Bee ;  6,  butterfly ;  c,  grasshopper ;  d,  fly ;  e,  bug ;  /,  beetle. 


SOME  INSECT  PESTS  AND  HOW  TO  FIGHT  THEM    325 

Some  insect  pests  and  how  to  fight  them.  —  We  must 
expect  certain  insect  pests  in  our  gardens,  and  because 
they  prefer  certain  foods,  only  one  or  two  kinds  of  insects 
will  attack  each  plant.  These  paragraphs  are  not  in- 
tended to  give  you  more  than  a  hint  as  to  the  insects  and 
what  to  do  to  destroy  them.  You  will  be  interested  to 
make  a  home  project  of  the  disposal  of  the  pests,  and  refer 
to  the  lists  of  bulletins  and  books  given  at  the  end  of  this 
chapter.  You  should  always  remember  that  where  poisons 
are  used,  they  are  poisons  to  younger  brothers  and  sisters, 
as  well  as  to  insects.  Keep  all  spraying  solutions,  and 
also  all  other  poisons,  well  out  of  the  reach  of  children,  and 
exercise  care  and  common  sense  in  using  them.  The  fol- 
lowing list  of  garden  vegetables  with  their  pests,  and 
methods  of  fighting  them,  will  be  found  useful. 


VEGETABLE 


INSECT 


PREVENTION  AND  CURE 


String  beans 


Cabbage 


Cauliflower 
Corn 


Cucumber 
Potato 


Squasta 


Aphids  (plant  lice) 


Bean  weevil  \ 
Bean  beetle  / 

Plant  lice 

Cabbage  worm 

Cabbage  borer 

Cabbage  worm 

Army  worm  (trav- 
els in  large  num- 
bers) 

Corn  root  worm 
Drill  worm 
Cutworm 

European    corn 

borer 

Cucumber  beetle 
Potato  beetle  (bug) 

Slugs 
Squash  borer 


Since  these  spread  from  weeds  to  beans,  keep  the 
weeds  and  other  plants  near  the  garden  cut. 
Spray  with  kerosene  emulsion  or  tobacco 
water. 

Use  same  spray  as  above. 

Soap  emulsion  or  tobacco  water. 
Use  Paris  green  and  pick  off  the  worms. 
Use  same  methods. 

Use  Paris  green  and  pick  off  the  worms. 
Dust  with  Paris  green,  or  if  numerous,  kill  by 
means  of  kerosene. 


Corn  dies.    Practice  crop  rotation. 

Crop  rotation. 

Cutworms  attack  the  silk  and  eat  the  end  of 

cob.     Spray  with  arsenate  of  lead. 
Report  to  state  authorities;    they  will  tell  you 

what  to  do. 

Dust  with  ashes  and  use  Paris  green. 
Watch  plants  and  pick  off  eggs  or  young  beetles 

early.     Spray  with  lime-Paris  green . 
Spray  with  Paris  green  or  arsenate  of  lead. 

Burn  vines,  practice  crop  rotation. 
Kill  young  with  kerosene. 


326 


PLANT  FRIENDS  AND  PLANT  PESTS 


Experiment.  To  illustrate  the  proper  way  of  making  some  insecticides  and 
fungicides;  lime-sulphur,  arsenate  of  lead,  Bordeaux  mixture,  and 
kerosene  emulsion. 

Prepare  several  of  these,  using  the  quantities  suggested  in  column 
"  For  Experiment  "  in  table  below.  This  table  shows  what  to  use 
and  how  to  prepare  the  most  commonly  used  garden  sprays : 


GARDEN 

AND 

ORCHARD 
USE 

FOR 

EXPERIMENT 

DIRECTIONS  FOR  MAKING 

LIME-SULPHUR 

Nearly  cover  the  lime  with  water.     When 

•      FUNGICIDE 

it  is    slaking  add  the  sifted   sulphur. 

For  Delicate  Foliage 
Quicklime      .     .     . 
Sulphur     .... 
Water            .     .     . 

2lb. 
2lb. 

12  gal. 

2  gm. 
2  gm. 

IOO  CC. 

Stir  constantly  and  add  a  little  water 
if  it  gets  very  dry.     After  five  min- 
utes   add    water    to    make    specified 
quantity. 

LIME-SULPHUR  SPRAY 

Mix  lime  and  sulphur  and  \  the  quantity 

For  Sucking  Insects 
Quicklime      ... 
Sulphur     .... 
Water            •     •     . 

4lb. 
3lb 
10  gal. 

3gm. 
85  cc. 

of  hot  water.     Boil  one  to  two  hours, 
or   until   it   has   a   dark  amber  color. 
Dilute     to    indicated     quantity     and 
apply  warm. 

ARSENATE   OF   LEAD 

Mix  the  arsenate  of  lead  thoroughly  in 

Spray  for  Chewing 

the  water. 

Insects 

Arsenate    of    lead 

paste  (use  |  the 

quantity  if  pow- 

dered is  used) 

i  ib. 

\  gm. 

Water 

12  gal. 

IOO  CC. 

BORDEAUX  MIXTURE 

Dissolve  the  sulphate  in  a  large  wooden 

Fungicide  and 
Germicide 

vessel,  or  in  a  glass  if  a  small  quan- 
tity.     Slake    the    lime     to    make    a 

Copper  sulphate     . 
Quicklime      .     .     . 
Water  

ilb. 
ilb. 
12  gal. 

i  gm. 
i  gm. 

IOO  CC. 

creamy   mixture,    then    add   water   to 
make  thin.     Strain  the  milk  of   lime 
through  cheesecloth  into    the  solution 
of  copper  sulphate. 

LIME-PARIS   GREEN 

Mix  the  Paris  green  and  water  and  add 

Spray  to  Control 
Potato  Beetle 

filtered  milk  of  lime. 

Paris  Green  .     .     . 

2  OZ. 

i  orn 

Lime    

ilb. 

1  gm. 

Water  

12  gal. 

IOO  CC. 

KEROSENE   EMUL- 
SION 

Dissolve   the  soap   in    about  £$  of  the 
water,    which    must    be    boiling    hot. 

Spray  for  Plant  Lice 
Hard  soap     .     .     . 
Kerosene  .... 

lib 
i  gal. 

igm. 

10  CC. 

Warm    the    kerosene    and    add.     Stir 
vigorously    until    creamy.      Add    the 
remainder  of  the  water. 

Water  (soft)  .     .     . 

12  gal. 

IOO  CC. 

INSECT  FRIENDS  327 

Insects  harmful  to  fruit  trees. — The  codling  moth  ruins 
$3,000,000  worth  of  fruit  each  year  in  New  York  state  alone. 
Most  of  us  know  this  pest  as  the  "  worm  "  in  the  apple. 
Spraying  the  trees  when  the  petals  begin  to  fall  is  the 
best  method  of  destroying  this  pest.  In  some  localities 
there  is  more  than  one  brood  of  codling  moths  in  sum- 
mer, in  which  case  the  spraying  has  to  be  repeated  for 
the  other  broods.  The  canker  worms,  tent  caterpillars, 
plum  curculio,  and  scale  insects  also  attack  fruit  trees. 
Borers  sometimes  do  much  injury  to  fruit  trees,  and  are 
very  hard  to  fight  as  they  work  into  the  tree  trunk  near 
the  ground.  Digging  them  out  and  filling  holes  with  car- 
bon bisulphide  are  the  best  ways  to  fight  them. 

Other  plant  enemies.  —  Those  of  us  who  have  lived  on 
the  farm  know  some  other  garden  pests.  The  ordinary 
cottontail  or  the  common  gray  rabbits  often  do  much 
damage  by  eating  garden  vegetables  and  fruits,  and  es- 
pecially by  gnawing  young  fruit  trees.  They  live  in 
burrows  which  they  dig  under  cover  of  weeds  and  thick 
grass.  They  breed  rapidly,  sometimes  having  several 
litters  of  from  two  to  four  each,  in  a  single  season.  Rats 
from  the  barn,  and  more  frequently  field  mice,  do  a  great 
deal  of  damage  to  our  gardens  and  trees.  The  ground 
mole,  although  in  some  ways  useful  because  of  its  diet 
of  insect  larvae  and  grubs,  digs  up  our  lawns  and  gardens 
so  as  to  become  a  pest  about  the  place. 

Insect  friends.  —  Everybody  knows  that  bees  are  useful 
for  they  not  only  make  honey  but  they  also  do  a  far 
greater  good  by  carrying  pollen  from  flower  to  flower,  thus 
aiding  in  the  growth  of  seed  and  fruits.  We  shall  discuss 
the  life  habits  of  bees  more  fully  in  our  next  book.  The 
ichneumon  flies,  near  relatives  of  the  bees,  are  of  much 


328 


PLANT.  FRIENDS  AND  PLANT  PESTS 


Two  valuable  garden  friends. 


value  to  man  because  they  lay  eggs  on  the  bodies  of  cater- 
pillars harmful  to  vegetation.     As  these  eggs  develop  the 

young  ichneumons 
live  on  the  body  of 
the  caterpillar  and 
eventually  kill  it. 
Some  beetles  are 
of  use  as  garden 
friends,  especially 
the  "  lady  bug  "  or 
lady  bird  beetle, 

which  feeds  upon  plant  lice  or  aphids.     Some  insects  feed 

upon  weeds  and  they  too  can  be  classed  as  our  friends. 
Other  garden  friends.  — 

Insects  and  some   animals, 

such  as  field  mice,  are  kept 

under  control  by  birds.     Our 

neighbor  the   robin,   whom 

we   sometimes    begrudge    a 

few  cherries,  is  of  more  use 

than   harm  because   of   his 

insect     diet.     Our     earliest 

visitor,   the   bluebird,   lives 

largely  on  injurious  insects, 

as     do     the     woodpeckers, 

cuckoos,      kingbirds,       and 

many  others.     Many  birds 

live  upon  insects  which  are 

most  numerous  around  them. 

When  great  numbers  of  in- 
sects are  present,  birds  do  an    Food  of  some  common  birds.     Which  of 

the  above  birds  should  be  protected  by 

immense  amount  Of  gOOd.  man  and  why  ? 


AMERICAN  CROW 


ENGLISH  SPARROW 


OTHER  FRIENDS  OF  THE  GARDEN 


329 


Birds  eat  weed  seeds.  —  Birds  also  help  us  in  our  gar- 
dens by  eating  weed  seeds ;  especially  beneficial  are  our 
native  sparrows  (not  the  English  sparrow),  the  bobwhite, 
the  mourning  dove,  and  others.  Those  birds  which  stay 
with  us  late  in  the  fall  often  devour  great  numbers  of  weed 
seeds,  which  are  thus  prevented  from  sprouting  and  grow- 
ing the  following  year.  Sometimes  birds,  such  as  owls, 
eat  rats,  field  mice,  and  other  pests.  We  should  all  band 
together  to  prevent  the  destruction  of  our  native  birds, 

and  to  encourage     

nesting  in  the 
trees  and  shrubs 
around  us.  House 
cats,  and  more 
often  stray  cats, 
are  of  great  harm, 
because  they 
either  kill  or 
frighten  away  the 
birds  and  prevent 
them  from  nest- 
ing in  the  neigh- 
borhood. 

Other  friends  of  the  garden.  —  We  do  not  think  of  a 
toad  as  being  a  beautiful  animal,  but  every  boy  and  girl 
who  keeps  a  garden  should  have  a  friendly  toad  living  under 
one  of  the  big-leaved  plants  in  it.  Toads  have  been  found 
to  eat  no  less  than  eighty-three  different  kinds  of  insects, 
most  of  which  are  injurious.  A  single  toad  has  been  esti- 
mated by  Kirkland,  on  account  of  the  cutworms  which 
it  might  kill,  to  be  worth  nearly  twenty  dollars  a  season, 
if  the  damage  done  by  each  cutworm  were  estimated  at 


The  common  toad,  an  insect  eater. 


330  PLANT  FRIENDS  AND   PLANT  PESTS 

only  one  cent.  Snakes,  most  of  which  are  harmless,  are 
also  garden  friends.  The  black  snake  and  milk  snake 
feed  largely  on  rats  and  mice,  while  the  common  green 
snake  eats  injurious  insects,  and  the  little  brown  De  Kay 
and  garter  snakes  have  a  diet  including  slugs,  which 
sometimes  do  much  damage  in  the  garden. 

REFERENCE   BOOKS 

Forbush,  Useful  Birds  and  Their  Protection.     Massachusetts  Board  of  Agriculture. 

Hodge,  Civic  Biology,  Chapters  IV,  XII,  XIV.     Ginn  and  Company. 

Hodge,  Nature  Study  and  Life,  Chapter  XVI.     Ginn  and  Company. 

Hunter,  A  Civic  Biology,  Chapter  XV.     American  Book  Company. 

Hunter,  Laboratory  Problems  in  Civic  Biology,  Chapter  II.  American  Book  Com- 
pany. 

Kellogg  and  Doane,  Economic  Zoology  and  Entomology,  Part  II,  Chapters  XXX, 
XXXII,  XXXIII,  XXXIV,  XXXV,  XXXVI.  Henry  Holt  and  Company. 

Mayne  and  Hatch,  High  School  Agriculture,  Chapters  V,  VI.  American  Book 
Company. 

Merriman,  Birds  of  Village  and  Field.     Houghton  Mifflin  Company. 

Moore  and  Halligan,  Plant  Productions,  Part  II,  Chapter  VII.  American  Book 
Company. 

Sanford,  The  Story  of  Agriculture  in  the  United  States.     Dl  C.  Heath  and  Company. 

Spillman,  Farm  Science,  Chapters  XII,  XIII,  XIV.     World  Book  Company. 

Trafton,  Science  of  Home  and  Community.     The  Macmillan  Company. 

Webster,  Value  of  Insect  Parasitism  to  the  American  Farmer.  U.  S.  Dept.  of  Agri- 
culture Yearbook,  1907. 

Weed,  Farm  Friends  and  Farm  Foes.    D.  C.  Heath  and  Company. 

U.  S.  Dept.  Agriculture,  Farmers'  Bulletins.  (There  are  very  many  of  these,  each 
treating  a  definite  insect  pest,  or  dealing  with  a  definite  fungus.)  Ask  to  be 
placed  on  the  mailing  list  for  the  monthly  list  of  bulletins.  Then  you  may 
select  and  send  for  those  which  interest  you. 


PART   VI.     DEVICES    FOR   LABOR 
SAVING   AND   CONVENIENCE 

CHAPTER  XXI 

SOME   SIMPLE   MACHINES    IN   THE   HOME 

Problems.  —  i.    To   understand   the   principles   underly- 
ing simple  machines  used  in  and  about  the  house. 
2.    To  understand  what  advantages  machines  offer. 

Experiments  and  demonstrations.  —  i .  To  demonstrate  the  principle  of 
levers. 

2.  To  illustrate  changing  speed  by  use  of  wheels  of  different  diameters, 
joined  by  belt  or  gears. 

Project  1.  — To  KEEP  THE  MACHINES  OF  THE  HOME  IN  GOOD  WORK- 
ING CONDITION. 

1.  Learn  how  to  operate  all  the  different  household  machines. 
Learn  what  oiling  is  necessary,  and  how  to  keep  free  from  dust 

and  dirt. 

2.  What  other  attention  is  needed  from  time  to  time? 

3.  Study  the  mechanism  of  the  more  complicated  machines  to 
know  how  the  machines  work. 

4.  If  needed  repairs  are  too  difficult  for  you  to  do,  be  ready  to 
advise  where  repairs  should  be  made. 

Suggested  Projects. 

I.  TO  DETERMINE  THE  TYPES  OF  MACHINES  AND  THE  MECHANICAL 
ADVANTAGE  OF  TEN  DIFFERENT  MACHINES  FOUND  IN  MY  HOME. 

331 


332        SOME  SIMPLE  MACHINES  IN  THE  HOME 

2.  TO   STUDY   THE   DIFFERENT   TYPES   OF  WASHING  MACHINES  AND 

DECIDE  WHICH  IS  BEST  SUITED  TO  HOME  USES. 

3.  PROCURE    HOUSEHOLD    SCALES.    HAVE    THEM    ADJUSTED    BY 
DEPARTMENT   OF  WEIGHTS   AND   MEASURES.    WEIGH    GROCERIES, 

MEATS,  ETC.,  BOUGHT,  AND  SEE  IF  CORRECT  WEIGHTS  ARE  DELIVERED. 

4.  TO  DETERMINE  HOW  A  LAWN  MOWER  WORKS,   WHAT  TYPES    OF 
SIMPLE    MACHINES    ARE    IN    IT,    AND    APPROXIMATELY    THE    RELATION 
OF  POWER  TO  WORK. 

5.  TO    DETERMINE    WHAT    MACHINE    PRINCIPLES    ARE    USED    AND 
HOW   THEY   ARE   APPLIED   IN  THE   DOOR  KNOB,    LATCH,    AND   LOCK. 

Thought  Questions. 

1.  May  the  hands  of  a  clock  be  considered  as  machines  of  the 
lever  type? 

What  class  of  lever  are  they,  and  what  advantages  as  machines 
have  they? 

2.  Explain  the  type  of  simple  machine  you  use  when  you  wind  a 
watch  or  a  clock. 

Why   we   use   machines   in   our  homes.  —  If   we  had 

lived  a  great  many  years  ago,  we  would  have  found 
that  there  were  very  few  devices  which  enabled  our  an- 
cestors to  save  labor  in  their  homes.  Much  work  was 
done  by  hand,  and  a  few  simple  machines,  such  as  churns, 
spinning  wheels,  wagons,  and  the  like,  were  used  to  do 
most  of  the  mechanical  work.  In  the  present  era,  an 
age  of  machinery,  we  have  come  to  save  time  and  also  save 
our  own  energy  by  using  machines  to  help  us  do  the  work. 
We  find  also  that  machines  are  usually  much  more  effi- 
cient than  we  are,  and  so  it  is  that  we  have  year  by  year  an 
increasing  number  of  devices  for  labor  saving  in  our  homes. 
Each  year  some  new  device  is  perfected,  and  it  is  a  wise 
housekeeper  who  can  select  from  such  a  multitude  of  ma- 
chines now  offered  in  the  market  those  which  are  mechani- 
cally perfect,  and  serviceable  and  durable.  It  is  the  pur- 


TWO  TYPES  OF  MACHINES  USED  IN  THE  HOME    333 


pose  of  this  chapter  to  point  out  a  few  of  these  machines, 
and  to  try  to  explain  the  simple  principles  which  underlie 
their  construction  and  regulation. 

Two  types  of  machines  used  in  the  home.  — The  lever 
and  the  wheel  and  axle  are  two  types  of  simple  machines 
which  play  an  important  part  in  the  construction  of  many 
household  devices. 
If  we  look  at  a  pair 
of  shears,  for  ex- 
ample, we  find  them 
to  be  made  of.  two 
pieces  of  metal,  held 
together  at  one  point 
by  a  rivet  with  the 
inner  edges  sharp- 
ened at  an  angle. 
If  we  try  to  cut  a 
piece  of  thick  cloth 
with  these  shears, 
we  find  it  much 
more  difficult  to  cut 
the  cloth  when  it 
is  placed  farther 
away  from  the  point 
where  the  parts  of 
the  shears  are  ro- 
tating, while  it  cuts 
much  easier  close  to  the  point  of  rotation.  The  shears 
illustrate  the  lever,  the  force  we  exert  being  called  the 
force,  the  resistance  we  overcome  in  the  cutting  of  the 
cloth  the  weight,  since  it  is  measured  in  units  of  weight, 
and  the  point  at  which  the  shears  revolve,  or  turn,  is  called 


In  which  of  each  of  these  three  cases  will  the  same  re- 
sistance be  overcome  by  a  smaller  force  ?  P=force. 
W=weight  (resistance).  F=fulcrum. 


334        SOME  SIMPLE  MACHINES  IN  THE  HOME 


the  fulcrum.  Another  example  of  such  an  instrument  is 
seen  in  the  sugar  tongs,  where  we  find  it  is  much  easier 
to  hold  the  lump  by  placing  the  fingers  close  to  the 
lump  than  it  is  if  we  were  to  apply  the  force  far  away 
from  it. 

The  wheelbarrow  is  a  lever.  Almost  any  boy  or  girl 
who  lives  in  the  country  knows  that  it  is  easier  to  carry 
a  heavy  load  on  the  wheelbarrow  if  the  load  is  placed 
nearer  to  the  wheel  than  to  the  handles  (see  diagram). 
The  nearer  the  load  can  be  placed  to  the  wheel,  the 
greater  the  ease  with  which  the  load  can  be  lifted  and 
carried.  All  of  these  machines  mentioned  use  a  common 
principle,  that  of  the  lever.  Let  us  now  study  and 
experiment  more  closely,  and  see  if  we  can  understand 
the  principles  underlying  it. 


Experiment.     To  demonstrate  the  principle  of  the  lever. 

Materials:  Ruler  with  hole  in  the  center.     Weights  and  string. 

Method:  With  the  lever  illustrated  find  out  where  a  force  of  i  pound 
must  be  applied  on  the  force  arm  to  balance  the  different  weights  sug- 
gested in  (a),  (6),  and  (c), 
applied  on  the  weight  arm. 
(a)  Place  2  pounds  2 
inches  from  the  fulcrum. 
(6)  Place  2  pounds  4 
inches  from  the  fulcrum. 
(c)  Place  6  pounds  i 
inch  from  the  fulcrum. 
Observation  and  conclusion: 
Where  will  a  force  of  i 
pound  need  to  be  applied 
to  balance  the  weight  in 
each  of  the  cases  (o),  (6), 
From  the  result  of  the  experiment  tell  what  is  wrong  an(j  (c)  p  can  you  work 

out  the  principle  of  levers 

by  comparing  the  forces  and  lengths  of  arms  in  each  case?     What 
statement  will  you  suggest  for  the  law  of  levers  ? 


F.  A  .  -  »*-WA. 


4  iV  T " " 


(weight) 


MECHANICAL  ADVANTAGE 


335 


Three  classes  of  levers. — There  are  three  classes  of 
levers  which  depend  on  the  position  of  the  fulcrum,  the 
weight,  and  the  force.  The  relative  positions  of  these 
are  as  follows :  In  levers  of  the  first  class,  the  fulcrum 
comes  between  the  weight  and  the  force ;  in  levers  of  the 
second  class,  the  weight  comes  between  the  fulcrum  and 
the  force ;  in  levers  of  the  third  class,  the  force  comes 


Levers  of  the  Tinst  Class 

/uJc'runv. 
y        ; 

/orce 


CD. 

•weight 


levers  y  the  Second  Clcrss 


/ulcru 


>reigrKt      /orce  • 


r   w 


r  w 


levers  of  the  Third  Class 


Common  examples  of  the  three  classes  of  levers. 

between  the  weight  and  the  fulcrum.  The  shears  belong 
to  the  first  class  of  levers,  the  wheelbarrow  to  the  second 
class,  and  the  sugar  tongs  to  the  third  class. 

Mechanical  advantage.  —  We  use  ordinarily  a  machine 
to  overcome  a  force  greater  than  that  which  we  apply.  If 
by  means  of  a  machine  we  can  lift  200  pounds  by  applying 
a  force  of  25  pounds,  then  the  mechanical  advantage  of 
the  machine  is  8 ;  it  is  equivalent  to  the  force  moved  di- 
vided by  the  force  applied.  With  levers  of  the  third  class 


336 


SOME  SIMPLE  MACHINES  IN  THE  HOME 


we  must  apply  more  force  than  the  resistance  to  be  over- 
come. Then  why  use  such  a  machine?  There  is  another 
advantage  for  which  some  machines  are  used,  that  is,  speed 
and  distance  moved.  The  advantage  of  levers  of  the 
third  class  is  that  of  speed  or  distance  covered.  Notice 
how  this  is  shown  in  the  sugar  tongs. 

How  we  weigh  things.  —  A  pair  of  scales  at  home  is  a 
necessary  thing,  for  it  may  save  more  than  its  cost  many 
times  over  in  checking  up  the  weight  of  groceries  and  other 
materials.  Most  scales  in  use  are  dependent  on  the  prin- 
ciple of  the  lever. 
In  the  scales  in  the 
picture,  can  you  tell 
whether  you  would 
get  more  or  fewer 
apples  if  the  sliding 
weight  were  placed 
at  point  A  or  at 
point  B  ?  Can  you 
explain  why  ?  An- 
other household  scale  not  dependent  on  the  principle  of  the 
lever  is  the  spring  balance.  To  explain  such  a  scale,  let 
us  suspend  a  coiled  wire  with  a  pointer  fastened  at  the 
bottom.  Let  us  now  fasten  to  the  wire,  weights  weighing 
10,  20,  and  30  grams  respectively.  As  the  weights  pull 
the  wire  down,  mark  the  position  of  the  pointer  on  the 
scale  representing  10,  20,  and  30  grams.  We  might  con- 
tinue this  scale  to  make  several  more  marks,  and  as  long 
as  the  elasticity  remained  in  the  wire,  we  could  then  use 
this  for  weighing  purposes.  This  is  the  principle  of  the 
spring  balance  or  postal  balance  used  for  weighing  letters. 
The  lawn  mower.  —  If  you  have  pushed  a  lawn  mower 


Principle  of  the  lever  used  in  weighing. 


K.U  IN  i\  .&«.:> 


661 


along  a  level  lawn,  you  must  have  noticed  that  the  force 
you  applied  is  distributed  in  two  directions.  You  push 
the  lawn  mower  forward,  but  you  also  push  it  downward. 
This  downward  motion  is  applied  in  increasing  the  pres- 
sure of  the  wheels  against  the  ground,  thus  causing  them 
to  turn  around  without  sliding.  The  horizontal  force 
is  used  in  moving  the  wheel  forward,  and  also  in  turning 
the  wheel.  If  you  turn  a  lawn  mower  upside  down  so  that 
the  revolving  knives  do  not  hit  the  grass,  you  will  notice 
that  it  runs  more  easily.  A  large  part  of  your  energy, 
then,  goes  in  moving  these  knives,  which  are  retarded  by 
pressure  against  the  grass  and 
the  lower  part  of  the  lawn 
mower.  If  two  boys  work  to- 
gether in  cutting  a  lawn,  the 
work  can  be  made  much  lighter 
by  one  boy  fastening  a  long  rope 
in  front  of  the  mower  and  pull- 
ing. Can  you  explain  why? 

Wheels  and  runners.  —  Why 
do  our  wagons  have  wheels  and 
our  sleds  runners?  Perhaps  you  know  that  when  we 
move  one  body  over  another,  a  certain  amount  of  re- 
sistance known  as  friction  must  be  overcome.  Have  you 
ever  pulled  with  all  your  might  to  drag  a  heavily  loaded 
box  over  the  floor  and  then  placed  one  or  more  rollers, 
such  as  can  be  made  from  a  broom  handle,  under  the  box 
and  found  how  easily  it  could  be  pulled?  In  much  the 
same  way  a  load  on  a  wagon  is  moved  over  the  bare  road 
more  easily  than  the  same  load  on  a  sled.  The  sled  runner 
slides  over  the  road  surface,  while  the  wagon  wheel  rolls 
over  it;  and  sliding  friction  is  greater  than  rolling  friction, 

H.-WHIT.    CIV.    SCI.    IN   THE   HOME  —  22 


The  push  (£)  is  divided  into  two 
parts:  force  A  downward,  which 
gives  the  necessary  friction  for  the 
wheels  to  turn,  and  force  C,  which 
rotates  the  blades  and  moves  the 
mower  forward. 


338        SOME  SIMPLE  MACHINES  IN  THE  HOME 


But  why  not  use  wheels  on  ice  and  snow?  If  you  ever 
tried  your  roller  skates  on  ice  you  know  the  difficulty 
of  getting  started.  This  is  because  of  the  lack  of  sufficient 
friction.  Such  smooth  surfaces  as  glass,  ice,  and  well- 
worn  snow  have  very  little  resistance  to  the  movement  of 
hard  objects  over  their  surfaces.  Sled  runners  have 

many  more  points 
of  contact  with  a 
supporting  surface 
than  have  wheels ; 
but  because  of  the 
very  low  friction 

Ball  bearings. 

between     ice     and 

smooth  steel,  steel  runners  are  better  for  snow  and  ice 
than  wheels.  With  skates  there  are  fewer  points  of  con- 
tact and  the  friction  is  sometimes  reduced  still  more  for 
another  reason.  When  skating  in  moderate  weather,  the 
pressure,  due  to  your  weight,  melts  the  ice  under  the  run- 
ners and  you  really  glide  over  water.  This  water  freezes 
instantly  after  the  skates  have  left  it. 

The  law  of  machines.  —  Machines  do  not  make  energy. 
They  simply  transfer  or  exchange  force  or  mechanical 
energy  from  one  place  to  another.  We  shall  see  as  we  go 
on  in  our  study  of  science  that  energy  is  simply  the  ability 
to  do  work.  Sometimes  this  energy  is  locked  up,  as  in  coal, 
which  gives  heat  when  burned,  or  it  may  be  evident  as  in 
the  power  in  the  running  stream,  or  in  the  waves,  or  in  the 
wind.  By  use  of  a  machine  we  may  transfer  this  energy 
or  power  from  one  place  to  another,  and  by  means  of  a 
machine  get  work  done  more  effectively.  The  chief  value 
of  machines  lies  in  their  enabling  us  to  overcome  a  large 
resistant  force  by  applying  a  small  force.  But  we  must 


THE  APPLICATION  TO   SOME  OTHER  MACHINES    339 


remember  that  we  can  get  no  more  work  out  of  a  machine 
than  we  put  into  it.  The  law  of  machines  may  be  stated 
as  follows  :  The  force  applied  to  a  machine  times  the  distance 
through  which  it  acts  equals  the  resistance  overcome  times 
the  distance  through  which  it  is  overcome.  That  is,  if  you 
move  a  2oo-pound  weight  i  foot  by  applying  a  force  of  20 
pounds,  this  force  would  have  to  act  through  a  space  of 
10  feet.  200X1  =  20X10. 

Unit  of  work.  — •  The  term  we  use  for  the  unit  of  work 
is  the  foot  pound.  This  is  exactly  what  its  name  indicates. 
If  we  lift  a  pound  one  foot,  the  result  is  a  foot  "pound,  or 
if  we  lift  four  pounds  four  feet  from  the  ground,  we  do 
sixteen  foot  pounds  of  work.  In  other  words,  the  work 
equals  the  weight  multiplied  by  the  distance. 

The  application  to  some  other  machines.  —  If  we  now 
apply  this  rule  to  such  other  machines  as  the  meat  chop- 
per, clothes  wringer,  coffee 
grinder,  and  ice  cream 
freezer;  we  find  that  we  can 
easily  estimate  the  amount 
of  force  which  must  be  ex- 
erted to  make  them  do  their 
work.  In  the  machines  just 
mentioned,  we  apply  force 
by  the  hand  with  a  crank  or 
handle  which  is  revolved 
through  a  circular  path.  All 
of  the  machines  belonging 
to  this  type  are  known  as 
the  crank  and  axle,  or  the  wheel  and  axle  type.  The  work 
is  done  at  a  point  on  the  circumference  of  the  axle.  If 
the  circumference  of  the  roller  of  the  clothes  wringer  is 


The  clothes  wringer;    a  crank  and  axle 
machine. 


340        SOME  SIMPLE  MACHINES  IN  THE  HOME 

six  inches,  and  the  circumference  of  the  circle  described  by 
the  hand  in  operating  the  handle  is  sixty  inches,  then  the 
resistance  of  200  pounds  at  the  roller  would  require  you  to 
expend  only  twenty  pounds  at  the  wringer  handle.  Ex- 
press this  in  terms  of  the  law  of  machines. 

Wheels  of  different  diameters  connected  by  belts  or 
interlocked  by  gear  teeth  are  used  for  the  purpose  of 
changing  speed  as  well  as  for  the  reason  of  mechanical 
advantage.  A  study  of  a  few  home  machines  will  make 
this  apparent  and  explain  the  purpose  of  their  use. 

Experiment.  —  To  illustrate  changing  speed  by  use  of  wheels  of  different 
diameters  joined  by  belt  or  gears. 

Materials:  A  Dover  egg  beater,  or  drill  with  gear  and  wheels.     Bicycle. 

Method:  (A)  Mark  one  point  on  the  working  part  of  the  egg  beater. 
Observe  how  many  times  this  revolves  for  one  complete  turn  of  the 
handle.  Try  this  three  times.  (B)  Count  the  number  of  cogs  on  the 
two  wheels  which  connect  the  force  end  of  the  machine  to  the  work  end. 
What  is  the  relation  of  the  numbers  of  cogs?  (C)  Make  similar  com- 
parison of  the  cogs  on  the  rear  axle  and  on  the  sprocket  wheel  of  your 
bicycle.  Find  the  number  of  revolutions  of  the  rear  wheel  to  one 
revolution  of  the  crank.  What  general  rule  regarding  change  of  speed 
is  suggested  to  you  by  these  observations? 

The  sewing  machine.  —  A  great  many  other  types  of 
machines  can  be  found  in  our  homes,  but  one  almost  al- 
ways present  is  the  sewing  machine.  Since  1850  these 
machines  have  been  improved  more  and  more,  so  that 
now  their  work  is  extremely  rapid  and  efficient.  A  study 
of  the  part  that  does  the  stitching  is  somewhat  too  com- 
plex for  us  at  the  present  time,  but  would  make  a  very 
interesting  home  project' which  could  be  studied  by  means 
of  diagrams  furnished  by  almost  any  good  machine  supply 
house.  One  good  project  which  could  be  worked  out  in 
the  laboratory  would  be  to  find  out  how  power  is  trans- 


OTHER  MACHINES 


341 


mitted  in  the  sewing  machine.  Notice  we  have  a  treadle 
which  transfers  power  to  the  drive  wheel.  If  we  measure 
the  diameter  of  this  wheel,  and  the  diameter  of  the  pulley 
over  which  the  belt  passes,  we  can  easily  determine 
how  many  revolutions  of  the  pulley  will  be  pro- 
duced by  one  revolution  of  the  drive  wheel,  then 
by  carefully  turning  the  pulley  one  complete  revo- 
lution, we  can  find  how  many  stitches  the  machine 
takes  in  each  complete  revolution.  This  is  only 
one  of  the  problems  which  can  be 
worked  out  in  connection  with  a 
sewing  machine. 

Other  machines.  —  A  number 
of  other  mechanical  principles  are 
found  in  many  machines  used  in 
the  home.  Among  them  are  the  inclined  plane,  the  wedge, 
the  screw,  and  the  pulley.  We  have  all  used  the  inclined 
plane  in  rolling  heavy  objects  like  the  barrel  up  a  grade.  And 
we  have  used  the  wedge,  which  is  really  two  inclined  planes 


B 


Observe  how  the  screw  is  in  reality 
a  spirally  inclined  plane.  Ex- 
plain diagram. 


Illustrating  the  use  of  the  screw. 


put  side  by  side,  points  together,  in  the  ax  or  hatchet.  The 
common  wedge  when  driven  into  the  wood,  forces  it  apart. 
The  screw  is  nothing  more  or  less  than  a  long  inclined 


342         SOME  SIMPLE  MACHINES  IN  THE  HOME 


plane  placed  in  the  form  of  a  spiral.  We  have  seen  the 
use  of  the  jack  screw  under  automobiles  in  case  of  tire 
trouble.  Again  it  is  simply  the  use  of  force  or  energy 
exerted  on  an  inclined  plane  which  runs  round  and  round 
the  jack.  Pulleys  are  not  used  so  often 
in  the  home  although  a  familiar  example 
is  seen  in  the  supports  of  the  painter's 
staging.  A  glance  at  the  diagram  will  show 
how  they  are  used. 

The  small  vacuum  washer.  —  Many  homes 
nowadays  have  washing  machines.  A  small 
hand  washer  using  the  vacuum  principle  does 
good  work.  The  cone-shaped  metal  washer  is 
fastened  to  a  handle  and  the  large  end  is 
open.  There  are  holes  in  the  sides  of  this 
cone.  If  this  washer  is  pushed  down  and 
lifted  up  alternately  with  a  great  deal  of  vigor, 
air  will  be  forced  out  on  the  down  stroke,  and 
the  vacuum  produced  on  the  up  stroke  sucks 
the  water  up  through  the  clothes  under  the 
washer.  The  use  of  such  an  instrument  as 
this  is  very  effective  in  washing  blankets  and 
delicate  materials  which  may  be  injured  by  rubbing. 
What  is  the  explanation  of  suction  ? 

Washing  machines.  —  Washing  machines  are  of  two 
kinds  as  far  as  the  inside  working  is  considered.  In  one 
the  system  of  vacuum  domes  is  similar  to  the  one  just  de- 
scribed and  is  operated  mechanically  inside  of  the  closed 
tub.  In  the  second  type  the  clothes  are  held  in  a  perforated 
drum  which  revolves  first  in  one  direction  and  then  in  the 
other.  This  drum  sets  in  water  held  in  the  outside  con- 
tainer. The  constant  whirling  of  the  water  back  and  forth 


With  this  pulley 
a  weight  of  600 
pounds  can  be 
supported  by 
a  force  of  100 
pounds. 


REFERENCE  BOOKS  343 

and  through  the  clothes  washes  them.  This  machine  may 
be  operated  in  a  number  of  different  ways,  by  hand 
lever,  crank,  water  motor,  or  electric  motor.  The  hand- 
operated  machines  are  very  efficient,  but  require  time  and 
attention.  The  motor-driven  ones  are  much  more  expen- 
sive, but  save  work. 

REFERENCE  BOOKS 

Bachman,  Great  Inventions  and  Their  Inventors  (Sewing  machine).    American  Book 

Company. 

Barber,  General  Science,  Chapter  X.    Henry  Holt  and  Company. 
Black  and  Davis,  Practical  Physics,  Chapter  II.     The  Macmillan  Company. 
Brownell,  General  Science,  Chapter  VII.     P.  Blakiston's  Son  and  Company. 
Caldwell  and  Eikenberry,  General  Science,  Part  III,  Chapters  XV,  XVI.     Ginn  and 

Company. 
Central  Scientific  Company,  Chicago,  Catalogue  with  illustrations  of  simple  machines 

for  projects. 
Child,  The  Efficient  Kitchen  (For  teachers),  Chapters  II,  XIV.    McBride,  Nast 

and  Company. 

Clark,  An  Introduction  to  Science,  Chapter  XXXII.     American  Book  Company. 
Clark,  The  Care  of  a  House  (For  teachers).    The  Macmillan  Company. 
Carhart  and  Chute,  Physics  with  Applications,  Chapter  VI.    Allyn  and  Bacon. 
Fall,  Science  for  Beginners,  Chapter  XXXIII.    World  Book  Company. 
Hessler,  The  First  Year  of  Science,  Chapter  X.     Benj.  H.  Sanborn  Company. 
Hoadley,  Essentials  of  Physics,  Chapter  III.     American  Book  Company. 
Hodgdon,  Elementary  General  Science,  Chapter  XIV.    Hinds,  Hayden  and  Eldredge. 
Knott    Apparatus  Company,  Boston.      Catalogues   with    illustrations   of   simple 

machines  for  projects. 

Lynde,  Physics  of  the  Household,  Chapters  I,  II,  III.    The  Macmillan  Company. 
Singer  Sewing  Machine  Company,  Mechanics  of  Sewing  Machines. 
Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  XV.    Houghton 

Mifflin  Company. 

.  Van  Rensselaer,  Manual  of  Home  Making  (Teachers'  use),  Chapter  III.   The  Mac- 
millan Company. 
Williams,  How  It  Works.    Nelson  Company. 


CHAPTER  XXII 

HOW   ELECTRICITY    IS   USED    IN    THE    HOME 

Problems.  —  i.    To  learn  the  properties  of  magnets  and 
how  magnetism  is  produced  by  electricity. 

2.  To  find  out  what  electromagnets  are   and   what  they 
will  do. 

3.  To  understand  the  working  of  electric  bells  and  how 
to  install  them. 

4.  To  find  out  how  a  simple  motor  works. 

5.  To  see  how  electricity  gives  heat. 

Experiments. —  i.   To  determine  laws  of  magnetic  poles. 

2.  To  magnetize  an  iron  bar  in  the  field  of  another  magnet  and  in  the 
earth's  magnetic  field. 

3.  To  make  an  electromagnet. 

4.  To  demonstrate  the  electric  bell. 

Project  I.  —  To  INSTALL  AN  ELECTRIC  BELL  IN  MY  HOME. 

1.  Plan  wiring,  bell  button,  and  battery  location. 
Concealed  or  outside  wiring.     Diagram. 

2.  Materials  needed. 

3.  Make  the  installation. 

Suggested  Projects. 

1.  TO  MAKE  A  COMPASS  OR  A  DIPPING  NEEDLE. 

2.  TO  MAKE  A  PERMANENT  PRINT  OF  A  MAGNETIC  FIELD. 

3.  TO  MAKE  A  TOY  ELECTRIC  MOTOR. 

344 


MAGNETS  AND  THEIR  PROPERTIES 


345 


Electricity  in  the  home. — Your  father  and  mother  can 
doubtless  remember  the  first  time  they  saw  the  trolley  car 
or  the  incandescent  light ;  it  was  only  a  few  years  ago  that 
the  wireless  was  first  used.  So  we  see  that  the  harnessing 
of  this  great  power,  electricity,  has  been  comparatively 
recent,  and  that  we  are  just  at  the  beginning  of  an  era  of 
electricity  and  electrical  devices.  Modern  households, 
if  well  equipped,  may  have  many  of  these  labor  saving  and 
useful  instruments.  There  are  three  general  types  of  elec- 
tric devices.  Examples  of  them  are  the  electric  door- 
bell, the  motor  which  drives  the  machine,  and  the  elec- 
tric iron.  The  bell  and  the  motor  depend  upon  electro- 
magnetic action  to  do  their  work,  while  the  iron  depends 
upon  the  heating  effect  of  the  electric  current.  In  order 
to  understand  even  a  little  about  these  devices,  it  is  neces- 
sary for  us  to  know  something  of  the  properties  of  elec- 
tricity, particularly  in  its  relation  to  magnetism.  Every 
boy  and  girl  has 
played  with  a  magnet 
or  some  toy  in  which 
a  magnet  was  used 
and  yet  may  not  know 
just  what  a  magnet 
is. 

Magnets  and  their 
properties.  —  A  great  The  magnetic  strength  is  greatest  near  the  ends> 
many  years  ago,  iron  ore  was  found  in  Magnesia,  Asia  Minor, 
which  had  the  property  of  attracting  to  it  other  pieces  of 
iron.  This  ore  was  called  magnetite,  and  the  name  magnet 
was  thus  derived  from  the  name  of  the  country  in  which  it 
was  first  found.  We  can  make  artificial  magnets,  either  by 
rubbing  a  piece  of  steel  with  a  natural  magnet,  or  by  hold- 


346    HOW  ELECTRICITY  IS  USED   IN  THE  HOME 


ing  it  near  one.  In  early  times  artificial  magnets  were 
always  made  in  this  way,  but  since  we  have  come  to  generate 
electricity  and  send  it  in  a  current  through  wires,  we  find 
that  we  can  make  better  magnets  by  its  use.  Of  this 
process  we  shall  learn  later. 

Experiment.  —  To  determine  laws  of  magnetic  poles. 

Materials:    A  bar  magnet.     A  suspended  magnet  (may  use  needle  of 

compass). 

Method  and  Results:  Bring  the  north  pole  of  the  bar  magnet  near  the  south 
pole  of  the  compass  needle.     Result?     Bring  the  south  pole  near  the 

north  pole.  Result? 
Make  similar  tests 
with  the  south  pole 
of  the  bar  magnet. 
Results? 

Conclusion:  Formulate 
a  law  concerning  the 
attraction  and  the  re- 
pulsion of  magnetic 
poles. 

The  properties  of 
magnets.  —  As  we 
have  seen  magnets 
attract  unmagnet- 
ized  iron  and  steel. 
They  will  also  at- 
tract two  other  met- 
als, nickel  and  co- 
balt. The  attractive 

What  law  of  magnetism  is  illustrated  here  ?  f Qrce  fe  greatest  near 

the  ends  of  the  magnets.  These  points  of  greatest  at- 
tractions are  called  the  poles  of  the  magnet.  Halfway 
between  the  poles  is  the  magnetic  equator,  a  region  of 
practically  no  magnetic  attraction.  If  a  magnet  is  sus- 
pended so  that  it  swings  freely  in  a  horizontal  plane,  it 


THE  MAGNETIC   FIELD 


347 


takes  a  north  and  south  direction,  the  pole  pointing  north 
being  called  the  north  pole,  and  the  pole  pointing  south, 
the  south  pole.  If  we  bring  the  north  pole  of  one  magnet 
near  the  north  end  of  a  suspended  magnet,  the  north  pole 
moves  away.  If  we  bring  the  south  pole  of  a  fixed  magnet 
to  the  north  pole  of  a  movable  one,  the  south  pole  is  drawn 
toward  the  north.  These  curious  facts  are  always  noticed 
when  two  magnets  are  brought  together,  and  from  this  we 
are  able  to  state  the  law,  which  is  as  follows :  Like  mag- 
netic poles  always  repel,  and  unlike  magnetic  poles  always 
attract,  each  other. 

The  magnetic  field.  —  It  is  not  necessary  to  touch  a  small 
piece  of  iron  such  as  a  tack  in  order  to  attract  it.  You 
have  often  noticed  tacks 
or  bits  of  iron  jump 
across  the  air  space  to  a 
strong  magnet.  A  com- 
pass needle  will  turn 
when  several  feet  away 
from  a  strong  magnet. 
These  facts  indicate  that 
the  influence  of  the  mag- 
net extends  in  all  direc- 
tions. This  force  de- 
creases as  the  distance 
increases.  The  space  about  a  magnet  in  which  magnetic 
influence  exists  is  called  the  magnetic  field.  It  is  because 
the  earth  itself  is  a  huge  magnet  and  has  surrounding  it 
a  magnetic  field,  that  the  compass  needle  takes  a  definite 
direction.  Every  magnetic  field  is  filled  with  magnetic 
lines  of  force  which  are  imaginary  lines  denoting  the  direc- 
tion of  the  magnetic  force. 


A  magnetic  field.  Iron  filings  scattered  over  a 
magnet  arrange  themselves  in  the  lines 
shown. 


348    HOW  ELECTRICITY  IS  USED  IN  THE  HOME 

Experiment.  —  To  magnetize  an  iron  bar  in  the  field  of  another  magnet  and 
in  the  earth's  magnetic  field. 

Materials:  A  three-inch  length  of  soft  iron.  A  strong  bar  magnet. 
A  three-foot  length  of  iron  gas  pipe  or  soft  iron  rod.  Compass.  Dip- 
ping needle.  Fine  iron  filings.  Hammer. 

Method:  (A)  Test  the  three-inch  iron  rod  by  dipping  it  in  iron  filings. 
If  it  shows  no  magnetic  effect,  place  one  end  of  it  very  near  to  one 
pole  of  the  bar  magnet.  Tap  it  two  or  three  times  with  the  hammer. 
Now  test  it  in  the  iron  filings  to  see  if  it  has  become  a  magnet. 
(B)  Test  the  iron  gas  pipe  by  holding  first  one  end  and  then  the  other 
near  the  north  end  of  the  compass  needle.  If  both  ends  attract  the  north 
pole  of  the  needle  it  is  not  magnetized  and  is  ready  to  use.  If  one  end 
attracts  while  the  other  repels,  its  magnetism  must  be  removed.  This 
may  be  done  by  holding  the  pipe  horizontally  in  an  east  and  west 
direction  and  striking  it  with  the  hammer.  After  a  few  trials  you 
will  find  that  its  magnetism  has  disappeared.  The  compass  indi- 
cates the  north  and  south  direction.  Place  the  dipping  needle  so 
it  is  free  to  swing  in  this  plane.  Hold  the  gas  pipe  in  a  position 
parallel  to  the  dipping  needle  and  strike  one  or  two  blows  on  the  end 
with  the  hammer.  Test  to  see  if  the  pipe  now  is  a  magnet  by  hold- 
ing first  one  end  and  then  the  other  near  the  compass  needle. 

Results  and  Conclusion:  What  are  the  results  in  (^4)  and  (B)?  What  is 
one  way  of  magnetizing  substances?  Why  does  the  dipping  needle 
take  the  direction  that  it  does?  Why  point  the  gas  pipe  in  that  same 
direction  ?  Why  do  tools  standing  in  one  place  in  the  house  sometimes 
become  magnets? 

Magnetic  property  of  an  electric  current.  —  If  a  wire 
connecting  the  two  poles  of  a  dry  cell  is  brought  down 
over  a  compass  in  a  north  and  south  line,  the  needle  will 
move  just  as  it  would  if  we  brought  another  magnet  near 
it.  This  is  evidence  that  a  magnetic  field  surrounds 
the  wire.  If  the  wire  is  coiled  by  winding  a  close  layer 
on  a  lead  pencil  and  a  current  sent  through  it  the  wire  will 
act  like  a  magnet  with  two  poles.  This  is  shown  by  bring- 
ing first  one  end  of  the  coil  and  then  the  other  end  near 
the  north  end  of  the  compass  needle,  for  one  end  will  at- 
tract and  the  other  end  will  repel.  The  coil  of  wire  behaves 


AN  ELECTRIC  BELL  SYSTEM  349 

like  a  magnet.  If  a  bar  of  soft  iron  be  slipped  inside  the 
coil,  it  will  act  as  before,  but  with  far  greater  strength. 
Such  a  device  as  this  last,  that  is,  a  bar  of  soft  iron  having 
a  current  of  electricity  passing  through  a  wire  surround- 
ing it,  is  known  as  an  electromagnet.  The  magnetic  prop- 
erty of  an  electromagnet  ceases  the  instant  the  electric 
current  is  shut  off,  and  appears  again  when  the  current 
is  turned  on.  The  electromagnet  is  the  basis  of  many 
household  devices,  some  of  which  we  are  now  going  to 
study. 

Experiment.  —  To  make  an  electromagnet. 

Materials:  Dry  cell.  Push  button.  Insulated  No.  20  copper  wires. 
Soft  iron  rod  three  inches  long.  Compass.  Small  iron  tacks. 

Method  and  Result:  (A]  Connect  one  pole  of  the  cell  to  one  screw  of  the 
push  button.  Connect  the  other  wire  to  the  other  pole  of  cell  and 
other  screw  of  push  button.  Bring  a  portion  of  the  wire  down  over  and 
parallel  to  the  compass  needle.  Press  the  button  to  cause  an  electric 
current  to  flow  through  the  wire.  Result?  The  current  flows  through 
the  wire  toward  the  zinc  pole  of  the  cell.  Make  diagram  to  show 
direction  of  the  current  through  the  wire,  and  which  way  the  north 
end  of  compass  needle  is  deflected.  (B)  Wind  the  insulated  copper 
wire  in  close  layers  around  the  soft  iron  rod,  remove  the  rod,  connect 
the  ends  of  the  coil  into  the  electric  circuit.  Hold  one  end  of  the  coil 
near  the  north  pole  of  the  compass  needle.  Press  the  button  to  pass 
an  electric  current.  Result?  Hold  the  other  end  of  the  coil  near 
the  north  end  of  the  compass.  Result?  Make  a  careful  diagram 
showing  the  windings  of  the  coil  and  connections  to  the  cell.  Let 
arrows  indicate  the  direction  of  the  current  in  the  wire.  Label  the 
north  and  south  poles  of  the  coil.  Put  the  iron  rod  inside  the  coil  and 
test  again.  Result? 

Conclusion:  How  can  you  make  an  electromagnet?  What  rule  can  you 
make  to  show  the  relation  between  the  direction  of  the  current  of 
electricity  around  the  coil  and  the  polarity  of  the  coil? 

An  electric  bell  system.  —  The  essential  parts  of  the 
electric  bell  system  are  the  bell,  connecting  wire,  the  but- 
ton, and  a  source  of  electric  current,  which  usually  is  the 


350    HOW  ELECTRICITY  IS   USED   IN   THE   HOME 

dry  cell.  The  button  is  a  device  for  making  and  break- 
ing the  circuit.  When  you  press  the  button  you  connect 
the  parts  of  the  wire  which  at  other  times  are  separated 
by  an  air  space.  Electricity  can  flow  only  when  there  is 
a  complete  metal  circuit  from  one  pole  of  the  battery 
back  to  the  other  pole.  The  wire  used  must  be  insulated 
to  prevent  leakage  and  short  circuits,  should  the  wire 
happen  to  come  in  contact  with  metal  or  wet  wood,  or  two 
parts  of  the  wire  come  together. 

Experiment.  —  To  demonstrate  the  electric  bell. 

Materials:   Electric  bell.     Electric  cell.     Wires.     Push  button. 
Method:  (A)  Study  the  bell.     Make  out  these  parts :  two  binding  posts, 

electromagnet,  armature,  spring,  contact  post,  contact  screw,  hammer, 

gong.     Trace  the  wire  connection  through  the  different  parts  from 

one  binding  post  to  the  other. 
Note:  In  some  bells  a  part  of  the  wire  circuit  is  omitted,  and  the  base 

of  the  bell  carries  the  current  from  one  part  of  the  bell  to  one  of  the 

binding  posts.     Is  that  the  case  with  the  bell  in  hand? 

Connect  bell,  cell,  and  button  in  circuit.     Adjust  contact  screw  if 

necessary.     Make  the  bell  ring. 
Explanation:  Explain  in  detail  just  why  the  bell  rings.     Make  diagram 

and  trace,  using  arrows,  the  passage  of  the  current  from  the  cell  back 

to  the  cell. 

How  the  bell  works.  —  The  bell  itself  consists  of  the  base 
support,  binding  posts,  electromagnet,  armature,  hammer, 
spring,  contact  post,  and  gong.  These  parts  are  all  shown 
in  the  diagram.  The  wires  from  the  battery  and  button 
are  connected  to  the  two  binding  posts ;  the  current  then 
goes  to  the  electromagnet,  to  the  spring  and  armature, 
to  the  contact  post,  and  thence  back  to  the  other  bind- 
ing post.  A  strip  of  platinum  on  the  armature  makes 
contact  with  a  platinum  point  from  the  contact  post. 
These  two  pieces  of  platinum  are  held  in  position  touching 
each  other  by  the  spring  when  no  current  flows. 


Now  suppose  the  circuit  is  closed  by  some  one  press- 
ing the  push  button.  A  current  flows  through  the  entire 
circuit.  The  electromagnet  attracts  the  soft  iron  arma- 
ture and  pulls  it  away  from  the  contact  point  at  P,  mak- 
ing a  gap  or  break 
in  the  circuit.  The 
current  instantly 
stops,  the  magnet- 
ism disappears,  the 
spring  (S)  brings  the 
armature  back  and 
closes  the  circuit,  a 
current  flows  again, 
and  everything  is  re- 
peated. This  back- 
ward and  forward 
movement  of  the 
armature  causes  a 
similar  vibration  of  the  hammer  which  strikes  the  gong 
on  every  pull  of  the  magnet.  This  vibration  and  result- 
ing ringing  of  the  bell  continues  as  long  as  the  button 
is  pressed. 

Sources  of  current.  —  The  dry  cell  has  about  the  same 
strength  as  the  wet  cell,  which  is  still  used  to  some  ex- 
tent. For  the  usual  house  circuit  two  cells  will  be  ample 
and  they  should  be  joined,  carbon  (inside  pole)  of  one  to 
zinc  (outside  pole)  of  the  other.  Either  one  of  these  types 
of  cells  needs  renewal  or  replacement  from  time  to  time. 
Where  electricity  is  used  for  lighting  it  is  possible  by  in- 
stalling a  special  device  for  reducing  its  pressure,  to  use 
it  for  the  doorbell  system.  The  device  used  is  called  a 
transformer.  A  transformer  made  for  bell  ringing  circuits 


The  electric  bell  system. 


352     HOW   ELECTRICITY  IS   USED   IN  THE   HOME 


can  be  bought  for  one  or  two  dollars.  The  cost  of  opera- 
tion is  about  the  same  as  for  renewals  of  batteries  in  the 
older  systems,  but  there  is  no  trouble  about  having  to  re- 
new batteries,  which  as  a  rule  means  an  interval  of  time 
when  the  bells  will  not  ring. 

The  telephone. -- The  telephone  can  almost  be  called 
the  errand  boy  of  the  household.  It  is  one  of  the  big- 
gest of  labor  savers.  There  are  a  number  of  complicated 

electrical  devices  in- 
volved in  the  com- 
plete equipment. 
The  receiver  itself 
has  an  electromagnet 
in  it  and  the  vibra- 
tion of  an  iron  disk, 
somewhat  similar  to 
the  vibration  of  the 
armature  of  the  elec- 
tric bell,  causes  sound 
waves  which  we  hear. 
A  more  complete  ex- 
planation of  the  tele- 
phone will  be  given 
when  we  study  com- 
munication at  a  fu- 
ture time. 

Commercial     mo- 
tors in  the  home.  - 
The    importance    of 
the  electric  motor  in 

the  home  can  well  be  appreciated  when  one  stops  to  think 
of  the  hard  hand  labor  which  is  replaced  by  motor-driven 


Electric  control  of  sewing  machine.     Find  the  motor 
which  drives  the  machine 


THE    VACUUM    Ul^AlM^K    AINJJ 


353 


washing  machines,  ice  cream  freezers,  grinding  wheels, 
sewing  machines,  vacuum  cleaners,  and  ironing  machines. 
They  are  inexpensive  for  the  amount  of  work  they  do, 
and  save  the  strength  of  the  housekeeper  for  other  impor- 
tant duties. 

The  vacuum  cleaner  and  sweeper.  —  The  electric 
vacuum  cleaners  are  of  two  types.  One  produces  a  vacuum 
by  means  of  an  air 
pump  of  the  piston 
type,  the  other  by 
means  of  a  fan.  A 
higher  vacuum  can 
be  produced  with 
the  pump;  and  yet 
a  very  high  vacuum 
is  not  needed:  in 
fact,  it  has  several 
disadvantages.  A 
strong  vacuum  is  hard  on  the  rugs  and  carpets,  or  any 
cloth  which  is  being  cleaned. 

The  principle  of  vacuum  cleaning  is  easily  demonstrated 
by  holding  the  end  of  a  glass  tube  near  a  loose  ball  of 
paper  (C)  and  drawing  up  the  piston  (A).  A  vacuum  is  pro- 
duced in  the  tube,  and  air  rushing  into  the  tube  pushes  the 
paper  along  with  it.  By  making  the  opening  (0)  smaller 
by  using  a  stopper  with  a  small  tube,  sand  may  be 
forced  into  the  tube,  and  if  a  piece  of  muslin  cloth  (m) 
is  fastened  over  the  inside  of  the  stopper  near  the  end  of 
the  larger  tube,  this  will  hold  the  sand  and  dirt  which 
enters,  but  will  allow  the  air  to  pass  on.  This  illustrates 
the  use  of  the  bag  for  holding  the  dirt  in  the  pump  cleaners. 
In  the  fan  cleaners,  however,  the  dirt  and  air  are  blown 

H.-WHIT.    CIV.    SCI.    IN   THE    HOME  —  23 


To  show  the  principle  of  vacuum  cleaning. 


354    HOW  ELECTRICITY  IS   USED   IN  THE   HOME 


into  the  bag.  The  dirt  is  held  here  by  the  tight,  close  mesh 
of  the  cloth,  but  the  air  passes  out  into  the  room  again 
after  being  filtered  through  the  cloth. 

For  thorough  cleaning  a  vacuum  of  TV  to  -f  of  an  at- 
mosphere is  desirable,  but  such  a  high  vacuum  makes  the 

tool  stick  to  the 
carpet  and  causes 
rapid  wearing.  For 
ordinary  sweeping 
where  it  is  desired 
to  remove  only  the 
surface  litter,  a  vac- 
uum of  TV  of  an 
atmosphere  is  suffi- 
cient. The  low  vac- 
uum machines  are 
termed  "vacuum 
sweepers  "  by  some, 
and  the  high  pres- 
sure machines  "vac- 
uum cleaners." 
There  are  numerous 
hand-driven  vac- 


uum sweepers  on 
the  market.  These 
give  a  lower  vacuum, 
as  a  rule,  than  the 
electrically  driven  ones,  and  yet  they  are  satisfactory 
for  superficial  sweeping.  Carpets  and  rugs  cleaned  by 
"  sweepers  "  need  removal  and  beating  occasionally. 

Electric  heating  devices.  —  Many  modern  homes  now  are 
equipped  with  electric  toasters,  grills,  coffee  percolators, 


Vacuum  cleaning  system. 


ELECTRIC  HEATING  DEVICES 


355 


Showing  the  resistance  wires  in  an  electric 
stove. 


chafing  dishes,  heating  pads,  curling  irons,  even  with  water 
and  room  heaters,  and  electric  ranges.  However,  the  electric 
flat  iron  is  by  far  the  most  popular  electric  device  so  far  intro- 
duced into  the  home .  The 
principle  of  electric  heat- 
ing is  practically  the  same 
in  all  of  them.  All  con- 
ductors resist  the  flow  of 
electricity.  The  electrical 
energy  used  in  overcoming 
the  resistance  becomes 
heat.  Some  metals,  like 
German  silver  and  nich- 
rome,  offer  much  greater 
resistance  than  copper  does.  For  that  reason  a  short 
length  of  nichrome  wire  would  give  as  much  heat  as  a  much 
longer  copper  wire  of  the  same  diameter.  It  is  advantageous 
then  to  use  a  wire  of  very  high  resistance  in  heating  de- 
vices where  the  heat  is  produced  by  electricity.  You  re- 
member when  studying  about  electric  lights  how  along  wire 

was  heated  by  an  elec- 
tric current.  When 
the  wire  is  in  position 
in  the  base  of  a  flat- 
iron  it  is  covered  with 
an  enamel  which  is 
baked  on  so  that  the 
wire  cannot  move  out 
of  position  or  touch 
other  parts  of  the  wire.  The  heating  element  of  the  coffee 
percolator  and  other  devices  is  made  essentially  in  the 
same  manner.  The  electric  iron  should  have  a  switch 


Electric  heating  pad. 


356     HOW  ELECTRICITY  IS   USED   IN  THE  HOME 


close  to   the  iron,  also   a  pilot  light  on   the  wall  socket 
where  it  is  attached.     This  pilot  light  will  always  glow 


An  electrically  prepared  meal.     What  heating  devices  do  you  see  ? 

when  the  current  is  left  on.  Many  fires  are  caused  every 
year  by  carelessness  with  electric  irons.  The  pilot  will 
suggest  to  you  the  danger,  and  you  will  be  less  likely  to 


Electric  toaster. 


Electric  iron. 


SCORE  CARD  357 

omit  turning  it  out  when  you  leave  it.     It  is  a  good  habit 
to  form  always  to  disconnect  at  the  socket. 

The  score  card.  —  This  score  card  will  help  you  to  be- 
come efficiency  experts  in  your  own  homes.  Mother  could 
be  saved  a  good  deal  of  labor  by  the  introduction  of  some 
of  the  machines  mentioned  here  and  no  doubt  your  home 
life  would  be  much  pleasanter  if  some  of  the  devices  listed 
here  were  added  to  your  own  list.  The  list  is  incomplete, 
so  space  has  been  given  for  you  to  credit  others.  If  you 
have  a  number  of  them,  talk  with  your  teacher  and  see 
if  you  can  substitute  some  you  have  for  others  you  do  not 
have  which  are  mentioned  on  the  card. 

REFERENCE  BOOKS 

Barber,  General  Science,  Chapter  X.     Henry  Holt  and  Company. 

Caldwell  and  Eikenberry,  General  Science,  Chapter  XIX.     Ginn  and  Company. 

Clark,  An  Introduction  to  Science,  Chapters  XXII,  XXIII,  XXIV.  American  Book 
Company. 

Clark,  The  Care  of  a  House,  Chapter  XI  (Teacher's  use).  The  Macmillan  Com- 
pany. 

Collins,  The  Book  of  Electricity  (Wiring  project).     D.  Appleton  and  Company. 

Fall,  Science  for  Beginners,  Chapters  XXX,  XXXI,  XXXII.  World  Book  Com- 
pany. 

Hessler,  The  First  Year  of  Science,  Chapter  VIII.     Benj.  H.  Sanborn  Company. 

Hodgdon,  Elementary  General  Science,  Chapter  XI.  Hinds,  Hayden,  and  Eldridge 
Company. 

Jameson,  The  Compass,  the  Signpost  of  the  World.  Taylor  Instrument  Company, 
Rochester,  N.  Y. 

Shafer,  Everyday  Electricity.     Harper  and  Brothers. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  XVI.  Houghton 
Mifflin  Company. 

Woodhull,  Electricity  and  its  Everyday  Use  (For  projects).  Doubleday,  Page  and 
Company. 


358    HOW  ELECTRICITY  IS  USED  IN  THE  HOME 


SCORE  CARD.    DEVICES  FOR  CONVENIENCE  AND  LABOR  SAVING 
IN  MY  HOME 


SCORE 


Perfect 
Score 


Electric  fixtures 

Doorbells 2 

Telephone 5 

Vacuum  cleaner 3 

Adjustable  fixtures  for  reading 2 

Electric  iron i 

Electric  cooker  or  heater i 

Other  devices  (name  them)        i 

Cleaning  helps 

Carpet  sweeper 2 

Dustless  mop  and  dusters i 

Washing  machine  or  vacuum  suction  washer  ....  2 

Clothes  wringer       i 

Gas  iron i 

Wall  ironing  board i 

Other  devices  (name  them)        . 2 

Kitchen  helps 

Fireless  cooker 2 

Gas,  electric,  or  blue  flame  stove        3 

Dishwashing  machine | 

Dish  drying  rack ^ 

Bread  mixer \ 

Meat  chopper \ 

Egg  beater \ 

Steam  cooker \ 

Ice  cream  freezer \ 

Knife  sharpener \ 

Other  devices  (name  them) .  i 

Other  helps 

Sewing  machine 5 

Electric  motor  or  water  motor  for  machine      ....  3 

Other  devices  (name  them)        ....:....  2 

Tools  and  workroom 

Tool  box  and  full  set  of  tools 3 

Carpenter's  bench  .     .     .     .    , i 

Proper  workroom i_ 

TOTAL 50 


CHAPTER  XXIII 

HOW  ELECTRICITY   IS    CONTROLLED    IN    OUR 
HOMES 

Problems.  —  i.    To  determine  how  electricity  is  produced 
and  controlled. 

2.  To  find  out  what  effect  different  lengths  and  sizes  of 
wire  have  on  the  electric  pressure  and  current. 

3.  To  find  out  how  the  house  is  protected  from  excessive 
currents. 

4.  To  learn  how  to  read  the  electric  meter. 

Experiment. —  i.   Make   a   wet   cell   and   show   presence   of   an   elec- 
tric current. 

Project  I.  —  To  INSTALL  A  NIGHT  LIGHT  IN  MY  BEDROOM. 

1.  Purpose  of  the  light? 

2.  How  will  you  arrange  wiring?     Locate  battery,  switch,  and 
lamp.     Make  plans  of  connections. 

3.  What  materials  are  needed?     Cost? 

4.  Install  the  light  system  and  make  a  report  on  it. 

Suggested  Projects. 

1.  THE    TRANSFORMER   VS.    DRY  CELLS    TO    OPERATE   A   DOORBELL. 

Find  the  cost  of  a  doorbell  transformer  for  use  on  electric  light  cir- 
cuit, and  cost  of  operating  it.  Find  cost  of  operating  doorbells  on 
dry  cells.  Considering  cost  and  convenience  of  uninterrupted  serv- 
ice, which  system  would  you  recommend  ? 

2.  FIND  THE  COST  OF  OPERATING  VARIOUS  ELECTRIC  DEVICES  PER 

HOUR.  Learn  how  to  measure  small  amounts  of  electric  power  by 
timing  the  revolutions  of  the  dial  in  the  wattmeter. 

359 


360 


HOW  ELECTRICITY  IS   CONTROLLED 


How  electricity  is  led  about  in  the  home.  — -  Although 
electricity  has  become  a  valuable  servant  and  a  cheap 
one  where  water  power  is  available,  yet  it  is  a  dangerous 
servant  as  well.  We  have  often  heard  of  fires  that  were 
caused  by  crossed  wires  making  a  "  short  circuit  "  or  by 

accidents  from  electric 
wires  of  heating  devices, 
or  of  people  shocked  to 
death  by  receiving  a 
charge  of  electricity  in 
their  body.  We  know 
that  the  wires  which 
carry  electricity  must  be 
carefully  guarded  by  a 
layer  of  what  we  call  in- 
sulating material,  that  is, 
something  that  will  not 
readily  conduct  the  elec- 
tricity. We  have  all 
learned  enough  about 
the  conduction  of  heat  to 

know  that  some  materials  are  good  and  some  are  poor  con- 
ductors. Likewise  certain  metals  will  conduct  electricity, 
while  other  substances,  like  rubber,  will  not  conduct  it, 
hence  the  latter  are  used  in  insulation. 

Current  electricity.  —  If  we  rub  wax  rapidly  with  a 
piece  of  woolen  cloth  we  can  electrify  it.  The  wax  is  then 
said  to  be  charged  with  electricity.  A  charged  body  such 
as  this,  is  one  in  which  electricity  is  at  rest.  To  be  sure, 
the  amount  in  the  wax  is  very,  very  small,  but  if  we  were  to 
connect  two  oppositely  charged  bodies,  negative  and  posi- 
tive, with  a  good  conductor,  such  as  a  metal  wire,  elec- 


The  sal  ammoniac  cell. 


ELECTRIC  CELLS 


361 


4  Posts 


BmdmeS 

i       to 


CccrboTL 

5cci\oL 
Sawdust 


tricity  would  flow  for  just  an  instant  from  one  body  to  the 
other.  Electricity  in  motion  as  this  is,  is  called  current 
electricity.  This  is  the  kind  of  electricity  which  we  use 
in  ringing  our  doorbells,  in  running  our  motors,  and  in 
lighting  our  homes.  We  have  all  seen  what  electricity 
will  do,  and  now  we  will  try  to  understaad  how  to  produce 
it,  and  some  other  things  which  we  can  do  with  it. 

Electric  cells.  —  You  may  have  heard  the  terms,  dry  cell 
and  wet  cell,  and  doubtless  some  of  you  have  seen  them  in 
your  homes,  as  these  two 
kinds  of  cells  are  used 
to  ring  electric  doorbells. 
The  wet  cell  is  made  by 
nearly  filling  a  jar  with 
a  saturated  solution  of 
sal  ammoniac.  In  this 
are  suspended  side  by 
side,  but  not  touching 
each  other,  a  large  car- 
bon plate  and  a  zinc  rod. 
Electricity  is  formed  at 
the  expense  of  chemical 
energy,  and  the  zinc  rod 
which  is  destroyed  must 
be  replaced  from  time 
to  time. 

In  the  dry  cell,  the 
zinc  used  is  placed  on 
the  outside  of  the  cell  while  the  carbon  is  a  large  rod  in 
the  center.  Between  these  are  the  chemicals,  a  paste  of 
sal  ammoniac  being  placed  next  the  zinc,  and  a  layer  of 
manganese  dioxide  around  the  carbon.  Dry  cells,  because 


is  WJ*?^ 


Sakxmmoniac 
and.  PI  aster 
y  'Paris 

'Porovcs  Tkpe 
-"Manganese 
DioxicLe  aria. 
'Powclerect 
Cccrrboru 


Heavy  Tar  Paper 


Section  of  a  dry  cell. 


362  HOW  ELECTRICITY  IS   CONTROLLED 

they  are  more  convenient  to  handle,  have  come  to  replace 
to  a  large  extent  the  wet  cell  in  our  homes. 

What  produces  the  electric  current  ?  —  When  an 
electric  cell  has  been  used  for  a  long  time,  it  may  refuse  to 
produce  any  more  current.  In  the  case  of  the  wet  cells, 
you  will  very  likely  find  that  one  of  the  plates  in  it  has 
been  used  up.  This  suggests  that  some  vigorous  chemical 
action  has  taken  place  in  the  cell  between  the  solution  and 
the  plates.  This  is  true.  The  cell  is  really  a  device  by 
which  energy  resulting  from  this  chemical  action  in  the 
cell  is  changed  into  electrical  energy. 

Experiment.  —  To  make  a  wet  cell  and  show  presence  of  electric  current. 

Materials:  Carbon.  Zinc.  Jar  for  sal  ammoniac  cell.  Sal  ammoniac. 
Electric  bell  or  compass.  Wires. 

Method:  Fill  the  jar  with  water  to  the  mark  and  add  sal  ammoniac 
and  stir.  Continue  adding  sal  ammoniac  until  a  saturated  solution 
is  obtained.  Put  zinc  and  carbon  in  cell.  Join  wires  to  poles.  Test  to 
see  if  a  current  is  produced  by  joining  an  electric  bell  in  circuit  or 
test  wire  of  closed  circuit  with  compass.  How  can  you  detect  a  current 
in  a  wire  by  means  of  a  compass? 

Result  and  Conclusion:  What  is  the  result?  What  are  the  essentials  of 
a  wet  cell? 

Wire  resistance  to  electricity.  —  Anybody  knows  that 
if  he  wants  to  empty  a  tank  of  water  a  short  pipe  would 
empty  it  quicker  than  a  long  one  of  the  same  diameter. 
This  is  explained  by  the  fact  that  a  long  pipe  has  more 
surface  to  rub  against  the  flowing  water,  and  this  produces 
iriction,  thus  allowing  less  water  to  get  out  in  a  given  time. 
There  is  a  very  close  parallel  to  this  in  the  case  of  elec- 
tricity passing  through  wires.  If  you  connect  the  poles 
of  one  cell  with  a  long  wire  and  then  the  poles  of  the  other 
cell  with  a  shorter  wire  of  the  same  diameter,  the  elec- 
tricity will  be  discharged  through  the  shorter  wire  more 


ELECTRICAL  PRESSURE 


363 


rapidly.  The  reason  for  this  is  that  the  longer  wire  offers 
greater  resistance  to  the  current,  so  that  less  current  flows ; 
but  as  in  the  case  of  the  tank  of  water,  the  current  will 
flow  for  a  longer  time. 

You  also  know  that  a  pipe  of  large  diameter  will  empty 
a  tank  of  water  much  quicker  than  one  of  small  diam- 
eter. A  large  tube  (or  pipe)  carries  a  larger  current  of 
water  than  a  small  one.  Just  so  with  electric  currents. 


Pipe 

(low  resistance)  I/or^PipeGnghresistaT 
Heavy  "Flow 


Short  Wire    I/ongWire, 
(low  resistance)  ("high,  resistance 
j  Large  3m  a  11 


Water  analogy:  short  and  long  wire  resistance. 

The  wire  with  a  large  diameter  permits  a  larger  flow  of 
electricity  than  one  of  small  diameter. 

Electrical  pressure.  —  Suppose  you  have  two  tanks  of 
water,  one  holding  a  large  amount,  and  the  other  a  small 
amount  and  that  the  water  in  them  is  kept  at  the  same 
level.  The  water  running  from  the  faucets  at  the  bottom 
will  have  the  same  pressure  just  so  long  as  the  level  is 
maintained  evenly  in  the  two,  and  if  the  openings  of  the 
two  faucets  are  of  the  same  size,  equal  streams  or  currents 
of  water  will  flow  from  them.  The  electrical  pressure 
(called  voltage)  is  independent  of  the  size  of  the  cells  used. 
The  cell  of  a  small  flashlight  may  have  just  as  high  pres- 
sure or  voltage  as  does  a  common  dry  cell  which  has  a 


HOW  ELECTRICITY  IS   CONTROLLED 


pressure  of  about  1.5  volts.  A  volt  is  the  unit  used  in 
measuring  electric  pressure,  or  the  force  which  causes 
electricity  to  flow  through  a  conductor.  An  instrument  for 
measuring  voltage  is  called  a  voltmeter. 

Electric  current.  —  If  we  use  our  tank  again  for  com- 
parison, we  shall  see  that  water  pressure  alone  will  not  tell 
us  how  great  a  flow  of  current  may  be  obtained.  The 
size  and  length  of  the  pipe  help  to  determine  this,  be- 
cause they  regulate  the  resistance,  and  resistance  is  one 
factor  which  determines  the  amount  of  water  which  flows. 


Equal 
Pressure 


Pipe  1/argfe.  T>ia  .  ^  \Pipe  5maU  Dice 
(Low  re5istance.)|P^\  (High  resi?tct 
Heccv-y  "Flow, 


j£l 

(7"Uv. 

i»    Ammeter 

Dry 

Equal 

Dry 

Cel 

* 

Voltage 

Cell 

U 

y 

Tlow. 


Wire  LargeDiameter  Wire  Simll  Dia.. 
(jow  resistccixcje.)  OughresistctJxcO 
L-arcffe  Guerrejxt,  Small  Current 


Water  analogy :  relation  of  current  to  resistance  in  large  and  small  wires. 

This  also  holds  in  a  similar  manner  with  electricity.  If 
we  have  the  poles  of  a  cell  connected  by  a  wire  of  small 
resistance,  a  large  current  will  flow  through  it,  but  if  the 
resistance  be  great,  a  small  current  will  flow.  The  unit 
for  measuring  an  electric  current  is  the  ampere,  so  named 
after  a  French  scientist.  The  instrument  by  which  this 
current  is  measured  is  the  ammeter. 

How  to  join  cells  for  use  in  the  home.  —  There  are  two 
ways  in  which  we  may  join  cells  together  so  that  we  can 
overcome  resistance  offered  by  wires.  These  are  in  series, 
and  in  parallel.  We  can  understand  these  terms  best  by  re- 
ferring again  to  our  water  tanks.  Suppose  we  have  three 


HOW  TO  JOIN   CELLS  FOR  USE  IN  THE  HOME    365 


tanks  of  water  at  the  same  pressure,  and  connect  them  so 
as  to  get  a  water  column  three  times  as  deep  as  that  of  a 
single  tank.  The  water  pressure  will  be  three  times  that 
of  a  single  tank.  If  we  join  three  cells  in  series,  that  is, 
zinc  to  carbon,  and  connect  a  voltmeter  in  the  circuit, 
we  shall  find  three  times  as  much  pressure  recorded  as  when 


Water  Xante  Aeries 
Pressure  \$  Increases 


WaterTahksiix'Parallel  .'Pressure  ofOneTank 


Water  analogy  to  illustrate  joining  cells  in  series  and  in  parallel. 

a  single  cell  is  attached  to  the  voltmeter.  A  high  pressure 
(high  voltage)  will  give  us  a  larger  current  (in  amperes) 
through  the  bell,  motor,  or  light  than  we  can  get  from  the 
low  pressure.  When  long  wires  are  used  in  connecting 
an  electric  bell  greater  voltage  is  required  to  overcome  the 
resistance  of  the  long  wire.  This  increased  volta'ge  can  be 
obtained  by  putting  in  one  or  two  more  cells  joined  in  series. 
A  bell  can  be  made  to  ring  louder  and  a  motor  to  run 
faster  by  this  same  method. 


366  HOW  .ELECTRICITY  IS   CONTROLLED 

When  we  join  our  three  tanks  of  water  at  the  same  level, 
we  increase  the  capacity  to  furnish  a  current  of  water, 
although  it  has  no  greater  pressure  than  the  single  tank. 
We  may  join  three  cells  in  parallel  by  connecting  all  the 
zinc  poles  to  one  wire,  and  all  the  carbon  poles  to  another 
wire,  then  we. join  these  two  wires  where  we  wish  to  use 
the  -current.  If  we  attach  a  single  cell  to  the  voltmeter 
and  read  the  voltage,  and  then  later  attach  three  cells 
joined  in  parallel  to  the  voltmeter  and  read  the  voltage, 
we  find  it  to  be  the  same.  Any  number  of  cells  joined  in 
parallel  have  just  the  same  voltage  as  a  single  cell.  With 
the  same  size  of  opening  for  the  single  and  the  triple  water 
tanks  the  water  would  flow  from  the  triple  tank  for  a  longer 
time.  It  has  a  larger  reservoir,  so  with  the  cells  joined  in 
parallel,  if  the  voltage  of  one  cell  gives  all  the  pressure  you 
need,  you  can  get  much  longer  service  from  several  cells 
joined  in  parallel  than  you  can  from  one  cell.  These 
explanations  should  serve  to  make  it  possible  for  you  to 
now  use  the  batteries  in  your  own  home  intelligently. 

The  life  of  a  cell.  —  If  you  have  a  large  outlet  to  a  tank 
of  water,  it  will  quickly  drain  the  tank.  The  less  re- 
sistance you  have  in  the  circuit  of  an  electric  cell,  the 
greater  will  be  the  flow  of  the  current,  and  since  the  ca- 
pacity of  a  cell  is  limited,  its  life  will  be  shortened.  The 
practice  of  connecting  two  poles  of  a  cell  by  a  short  piece 
of  metal  quickly  spoils  the  cell.  If  you  wish  your  cell  to 
work  for  you  for  a  long  time,  be  sure  not  to  allow  any 
"  short  circuits." 

What  is  a  "short  circuit"?  — We  have  all  used  the 
term  "  short  circuit,"  and  now  let  us  try  to  understand 
fully  what  it  means.  The  circuit  of  electricity  is  the 
complete  path  which  the  current  must  take  from  the  cell 


•c 


FUSES  367 

out  around  the  wire,  through  the  bell,  or  other  instru- 
ment, and  back  to  its  starting  point.  Let  us,  for  example, 
take  the  lighting  system  in  our  home.  Current  is  brought 
into  the  house  by  one  wire,  and  returns  to  its  source  by 
another.  If  in  the 
diagram,  A  and  B 
connect  our  house 
circuit  with  the  city 
supply,  when  the 
switch  is  closed  we 

are  able  tO  light  any  Diagram  of  lighting  system. 

one  or  all  of  the  lights  L,  L',  and  L" .  These  lamps  have  a 
high  resistance  to  electricity,  and  allow  not  more  than  one 
to  three  amperes  of  current  to  flow  through  the  circuit. 
Now  suppose  the  bare  ends  of  the  wires  C  and  D,  which 
have  low  resistance,  are  brought  together.  This  "  short 
circuit "  would  reduce  the  resistance  several  hundred  times, 
and  the  current  would  be  increased  enormously. 

There  is  a  real  danger  from  short  circuits.  Not  only 
may  the  insulation  on  wires  be  burned  off,  but  the  build- 
ing may  be  set  on  fire.  If  any  part  of  the  wire  AC  is  con- 
nected metal  to  metal  with  any  part  of  BD,  or  if  the  two 
separated  metal  parts  of  the  lamp  circuit  be  joined  by  a 
piece  of  metal,  a  short  circuit  results,  with  its  great  in- 
crease of  heat  and  corresponding  danger  from  fire.  When 
the  dry  cell  is  "  short  circuited  "  there  is  much  less  danger 
from  fire  than  in  the  case  of  the  electric  light  circuit,  be- 
cause the  cell  has  a  very  small  capacity.  Yet  this  cell 
will  heat  a  short  length  of  small  iron  or  german  silver 
wire  red  hot,  and  so  might  be  a  source  of  danger. 

Fuses.  —  If  we  were  to  take  a  number  of  different  metals 
and  expose  them  to  heat,  we  would  find  that  some  of  them 


368 


HOW  ELECTRICITY  IS   CONTROLLED 


TXIIC- A. 
PORCELAIN 
FUSE   WIRE 

SCREW  CONTACT 

PORCELAIN 

"POINT 


melt  at  a  much  lower  temperature  than  others.  Lead, 
for  example,  melts  very  readily.  If  you  have  seen  the 
plumber  solder  pipes,  you  have  noticed  that  he  has  a  copper 
instrument  which  is  used  to  melt  the  solder,  so  you  know 
that  red  hot  copper  can  melt  solder.  Such  low  melting 
metals  are  used  in  making  fuse  wires.  If  a  fuse  wire  is  made 

a  part  of  the  elec- 
trical circuit  in  a 
house,  it  would  evi- 
dently melt  if  heated 
to  a  point  much 
below  that  which 
would  melt  the  cop- 
per wires  carrying 
electricity.  Such  a 
c.Link  wire  placed  in  the 
house  circuit  is 
known  as  the  fuse.  If  a  short  circuit  is  produced,  the 
fuse  instantly  melts,  and  thus  the  electricity  is  cut  off  from 
the  house,  and  danger  from  fire  prevented.  If  we  have 
electric  lights  in  our  home,  we  should  all  know  the  loca- 
tion of  the  fuse  box,  and  we  should  understand  how  to 
put  in  the  fuse  plugs  in  case  they  burn  out.  Of  course, 
we  must  take  care  first  to  turn  back  the  switch,  thus  cutting 
off  all  the  electricity  from  the  house,  before  we  attempt  to 
do  this. 

Measuring  electricity.  —  Each  one  of  us  should  learn 
to  read  the  dials  on  the  ordinary  electric  meter,  which  is 
part  of  the  equipment  of  every  house  that  takes  its  elec- 
tricity from  the  city  supply.  The  meter  is  called  the 
wattmeter,  and  the  readings  are  made  in  kilowatt  hours. 
For  example,  if  we  have  ten  lamps,  each  marked  twenty- 


Fuses  :   A,  Cartridge  fuse ;    B,  Socket  fuse ; 
fuse. 


MEASURING  ELECTRICITY  369 

five  watts,  and  they  are  all  lighted  for  an  hour,  we  would 
then  be  using  10X25  or  250  watts  an  hour,  and  in  five 
hours  this  would  be  5X250  or  1250  watt  hours.  The  watt 
is  the  unit  by  which  we  measure  electrical  energy.  One 
thousand  watts  make  one  kilowatt  and  one  kilowatt  used  for 
one  hour  equals  one  kilowatt  hour.  Electricity  for  the  ten 
lamps,  using  1250  watt  hours  or  1.25  kilowatt  hours,  would 
cost,  at  twelve  cents  per  kilowatt  hour,  fifteen  cents  per 
hour.  A  study  of  the  diagram  shows  that  of  the  four  dials, 
the  one  to  the  left  moves  the  least,  while  the  one  to  the  right 
moves  the  fastest.  The  four  dials  indicate  thousands, 
hundreds,  tens,  and  units.  Study  the  diagram.  If  the 
thousands  hand  is  between  i  and  2,  it  will  indicate  1000 ; 
if  the  hundreds  hand  is 
between  6  and  7,  it  in- 
dicates 600;  if  the  tens 
hand  is  between  5  and 
6,  that  will  be  50,  and 
the  units  hand,  between 

,  .  ,  Wattmeter  dials. 

9    and    o,    is    read    9, 

making  a  total  of  1659  kilowatt  hours.  If  the  previous 
reading  had  been  1610,  that  would  mean  that  we  have  used 
49  kilowatt  hours  since  the  meter  was  last  read.  We  have 
already  shown  under  the  chapter  on  lighting  some  ways 
to  reduce  the  'electric  light  bill  through  the  use  of  the 
tungsten  lamps,  but  if  our  meter  bill  seems  high,  we 
should  inquire  into  the  cause.  The  large  bill  may  come 
from  some  leakage,  from  a  forgotten  light  in  a  closet  or 
attic  left  burning,  from  defective  wiring  which  may 
allow  a  current  to  flow  when  no  lights  are  in  use,  and 
rarely  from  an  error  in  the  meter  itself,  or  in  the  reading 
of  the  meter  by  the  man  sent  from  the  electric  company. 

H.-WHIT.   CIV.   SCI.   IN   THE   HOME  —  24 


370  HOW  ELECTRICITY  IS   CONTROLLED 

REFERENCE  BOOKS 

Bachman,  Great  Inventors  and  Their  Inventions  (Edison).   American  Book  Company. 

Baker,  Boys'  Second  Book  of  Inventions.     McClure  Phillips  Company. 

Book  of  Knowledge,  Articles  on  Electricity.     Grolier  Society. 

Butler,  Household  Physics.     Whitcomb  and  Barrows. 

Caldwell  and  Eikenberry,  General  Science,  Chapter  XVII.     Ginn  and  Company. 

Clark,  Introduction  to  Science,  Chapter  XXIV.     American  Book  Company. 

Clark,  The  Care  of  a  House,  Chapter  XI  (For  teachers).     The  Macmillan  Company. 

Croft,  Wiring  for  Light  and  Power  (For  teachers).     McGraw  Hill  Book  Company. 

Knox,  All  About  Electricity.    Funk  and  Wagnalls. 

Lynde,  Physics  of  the  Household,  Chapters  XIX,  XX,  XXI.  The  Macmillan 
Company. 

Morgan,  The  Boy  Electrician  (For  projects).     Allyn  and  Bacon. 

New  International  Encyclopedia,  for  lives  of  great  discoverers  of  electricity.  Dodd, 
Mead,  and  Company. 

Romance  of  Modern  Electricity.     J.  B.  Lippincott  Company. 

Tappan,  Wonders  of  Science,  "Interviews  with  Edison."  Houghton  Mifflin  Com- 
pany. 

Van  Buskirk  and  Smith,  Science  of  Everyday  Life,  Project  XII.  Houghton  Mifflin 
Company. 


PART   VII.     RECREATION    IN    THE 
HOME 

CHAPTER  XXIV 
INDOOR   RECREATION 

Problems.  —  i.    To  learn  the  nature  of  sound  and  the  re- 
lation of  our  voice  and  ears  to  sound. 

2.  To    learn   simple   principles   underlying   music    and 
musical  instruments. 

3.  To  cultivate  the  habit  of  reading  good  books. 

4.  To  see  how  to  get  the  most  home  enjoyment  in  stories 
and  games. 

5.  To  learn  some  ways  to  have  fun  with  mechanical  and 
electrical  toys. 

Experiments  and   demonstrations.  —  i.   To   show   that  sound  is  due 
to  vibration. 

2.   To  demonstrate  static  electricity. 

Project   I. — To   UNDERSTAND   THE   MECHANISM  OF  THE  PIANO 

AND  THE  PIANO  PLAYER. 

1.  The  wires,  relation  of  sizes,  lengths,  tension.     How  tuned? 

2.  Key  action?    Diagram  to  show  it.    Keyboard?    Octaves? 

3.  Pedals.     Action  and  control? 

4.  Player  —  pump  —  air  pressure  or  exhaust.    How  does  air  con- 
trol key  action?     Use  of  the  music  roll? 

37i 


372  INDOOR  RECREATION 

Suggested  Projects. 

1.  TO  LEARN  HOW  TO  BE  A  VENTRILOQUIST. 

2.  TO  BUILD  A  CANTILEVER  BRIDGE  WITH  A  MECCANO  OUTFIT. 

3.  TO  LEARN  TO  PLAY  SOME  MUSICAL  INSTRUMENT. 

4.  TO  LEARN  TO  SING  OR  TO  TELL  A  STORY  WELL. 

5.  TO  START  A  STAMP  COLLECTION  AND  SPECIALIZE  IN  THE  STAMPS 
OF  SOME  ONE  COUNTRY. 

6.  TO  LEARN  TO  DO  ELECTROPLATING. 

The  place  of  recreation  in  our  lives.  —  We  hear  a 
great  deal  nowadays  about  the  eight-hour  day.  The 
average  day  of  the  working  man  or  the  business  man  or 
woman  should  give  eight  hours  for  work,  eight  hours 
for  sleep,  and  eight  hours  for  other  duties  of  life,  includ- 
ing recreation.  In  our  school  day,  even  more  time  is 
allowed  for  play.  But  much  of  this  time  is  spent  away 
from  home.  We  are  getting  far  too  fond  of  spending 
time  away  from  home,  especially  in  the  evenings.  How 
much  better  it  would  be  for  every  boy  and  girl  to  feel 
that  two  or  three  hours  in  the  evening  should  be  spent  in 
the  family  circle.  Too  many  movies  and  not  enough  home 
life  are  the  choice  of  the  average  boy  and  girl  of  to-day. 
We  usually  have  access  to  the  well-lighted  reading  room 
of  the  public  library.  But  nothing  can  take  the  place  of 
home,  and  the  remembrance  of  the  pleasant  evenings  spent 
before  the  open  fireplace,  or  playing  games,  or  reading 
around  the  comfortable  lamp  in  the  living  room,  should 
be  the  heritage  of  every  boy  and  girl  who  reads  this  book. 

Sound  in  relation  to  our  home  life.  —  Have  you  ever 
stopped  to  think  what  our  home  life  would  be  without 
sound?  No  mother's  or  father's  voice,  no  conversation  at 
the  table,  no  music,  vocal  or  instrumental,  no  phonograph, 
none  of  the  hundreds  of  pleasant  and  interesting  events 


WHAT  IS  SOUND? 


373 


which  follow  the  use  of  our  voices,  for  withou:  sound 
means  without  voice.  You  will  be  glad,  now,  to  get  a  little 
information  about  sound  in  its  relation  to  human  beings. 

What  is  sound  ?  —  We  know  in  a  general  way  that  we 
make  sounds  by  means  of  certain  cords  in  our  throats, 


Enjoying  life  at  home. 

called  the  vocal  cords,  and  that  sounds  affect  our  ears,  which 
in  turn  communicate  them  to  the  brain,  and  we  get  the 
sensation  we  call  sound.  But  this  does  not  explain  how 
sound  originates. 

Experiment.  —  To  show  that  sound  is  due  to  vibration. 

Materials:  Tuning  fork.     Pith  ball  on  end  of  a  thread.    Glass  of  water. 

Method  and  Results:  Strike  the  prong  of  a  tuning  fork  on  a  block  of  wood. 
Rest  the  handle  end  against  the  table.  Let  the  pith  ball  suspended  by 
the  thread  come  in  contact  with  the  prong.  Result  ?*  Strike  the 
prong  again  and  touch  the  surface  of  the  water  with  it.  Result? 
Pluck  a  stretched  string.  Touch  with  the  pith  ball.  Result? 

Conclusion:  Do  these  bodies  produce  sound  except  when  they  are  vi- 
brating? How  does  a  body  produce  sound? 


374 


INDOOR  RECREATION 


When  the  alarm  clock  goes  off  in  the  morning,  it  makes 
no  difference  what  part  of  the  room  it  is  in.  Sound  travels 
from  it  in  all  directions.  If  we  obtain  a  tuning  fork,  an 
instrument  which  gives  a  musical  tone,  we  shall  be  able 
to  learn  something  about  how  sound  is  produced.  If 
we  strike  the  prongs  of  the  fork  on  a  block  of  wood,  we 
are  all  able  to  hear  the  sound,  although  we  cannot  notice 
that  the  tuning  fork  looks  any  different  than  it  did  before 
it  was  struck,  but  if  we  hold  a  pith  ball  suspended  from  a 
string  so  that  it  touches  the  prong  of  the  fork,  after  the 
fork  has  been  struck,  we  notice  that  the  pith  ball  moves 

violently  away  from  the 
fork,  as  if  struck  by  a  blow. 
If  we  now  stick  the  end  of 
the  fork  into  a  vessel  of 
water,  we  find  a  fine  spray  of 
water  thrown  from  the  sur- 
face. Evidently  the  fork  is 
in  quite  rapid  motion.  As 
a  matter  of  fact,  it  is  vibrat- 


How  to  show  that  a  sounding  tuning  fork 
is  in  motion. 


ing  several  hundred  times  a 
second,  and  in  vibrating,  it 
strikes  the  air  just  as  it  strikes  the  water,  and  sets  up 
little  waves  in  the  air.  Just  as  waves  move  on  the  sur- 
face of  water  when  we  drop  a  stone  in,  becoming  wider 
and  wider  as  they  move  away  from  their  source,  so  a 
body  that  makes  sound,  as  the  tuning  fork,  sends  these 
waves  off  into  the  air.  Only  we  must  remember  that 
instead  of  the  waves  moving,  as  on  the  surface  of  the 
water,  in  one  plane  only,  these  are  moving  away  in  all 
directions  from  the  sounding  body,  each  wave  making  a 
hollow  sphere  in  the  air. 


DIFFERENCES  IN  THE  PITCH  OF  THE  VOICE    375 


Vocal  cords. 


Our  voice.  —  A  study  of  the  figure  will  show  us  the  lo- 
cation of  the  vocal  cords,  which  are  instrumental  in 
producing  sound.  They  are  composed  of  two  thin  struc- 
tures stretching  from  front  to  back  across  the  voice  box, 
near  the  top  of  the  lar- 
ynx. They  are  attached 
to  the  side  walls.  By 
means  of  muscles  the 
tension  of  these  cords 
may  be  changed  and  the 
size  of  the  opening  be- 
tween the  two  outer 
edges  may  be  made  larger  or  smaller.  In  deep  breath- 
ing, for  example,  they  lie  flat  against  the  side  walls  of 
the  larynx,  thus  allowing  a  full  entrance  of  air.  But 
when  we  make  a  sound  they  come  very  close  together 
so  that  only  a  narrow  opening  is  made  between  them. 
The  tightly  drawn  cords  are  set  into  vibration  by  the 
passing  air,  and  sound  results. 

Differences  in  the  pitch  of  the  voice.  —  A  child's  voice 
is  shrill  or  high  pitched.     This  is  because  the  larynx  is 

narrow  and  the  vocal 
cords  are  short.  It 
is  a  well-known  fact 
that  long  wires  or 
strings,  when  vibrat- 
ing, give  a  much 
lower  and  deeper 
tone  than  do  short  strings.  This  is  easily  seen  in  picking 
the  mandolin  or  banjo.  If  you  put  your  fingers  on  the  frets, 
making  the  string  shorter,  it  gives  a  note  of  higher  pitch. 
When  a  boy's  voice  is  breaking  or  changing,  it  means  there 


The  pitch  of  a  string  is  raised  by  shortening  the  wire 
and  by  increasing  the  tension  on  it. 


376  INDOOR  RECREATION 

is  a  sudden  growth  of  the  larynx,  and  in  consequence,  a 
lengthening  of  the  vocal  cords.  This  change  is  so  rapid 
that  there  is  an  uncertainty  in  the  boy's  control  of  his  vocal 
cords,  and  the  break  in  the  voice  occurs. 

How  we  talk.  —  Human  speech  seems  very  wonderful, 
and  yet  it  is  all  accomplished  after  we  have  learned  how 
to  control  the  voice  with  absolute  unconsciousness  on  our 
part.  When  we  speak  in  a  monotone,  all  of  our  words 
are  of  the  same  pitch,  and  yet  we  can  distinguish  differ- 
ences in  the  sound  of  the  different  words.  This  is  due 
to  the  quality  of  sound.  As  the  sound  waves  pass  through 
the  mouth,  they  are  changed  in  quality  by  movements 
of  the  tongue,  soft  palate,  cheeks,  jaws,  and  lips.  A 
study  of  your  own  voice  before  a  mirror  while  you  make 
the  sounds  a,  e,  i,  o,  and  u,  will  show  you  that  in  each 
of  these  sounds,  a  different  position  of  the  parts  of  the 
mouth  and  throat  are  assumed.  It  is  excellent  practice 
for  any  one  who  is  troubled  in  enunciation  to  thus  stand 
before  a  mirror  and  practice  making  these  sounds,  for  it 
is  only  by  practice  that  our  mouth  parts  unconsciously 
get  the  habit  of  forming  sounds  correctly,  and  thus  we 
learn  to  speak  clearly.  Get  this  habit  of  clear  enuncia- 
tion while  you  are  in  school,  and  it  will  remain  with  you 
as  a  good  habit  through  life. 

How  we  hear.  —  Sound  and  speech  would  not  be  of 
much  use  to  us  if  we  could  not  hear.  The  ear  is  far  too 
complicated  and  delicate  an  organ  for  us  to  understand 
at  this  time,  although  a  study  of  the  accompanying  dia- 
gram will  give  us  some  idea  of  how  sound  is  heard.  The 
outer  ear,  which  is  simply  an  organ  to  help  gather  the 
sound  waves,  leads  by  means  of  a  tube  into  the  middle 
ear.  This  is  separated  from  the  outer  ear  by  a  delicate 


HOW  WE  HEAR 


377 


membrane.  If  this  membrane  is  broken,  hearing  is  im- 
paired, and  therefore  children  should  be  very  careful  not  to 
stick  a  pointed  instrument  into  the  ear,  and  if  anything  gets 
into  the  ear,  they  should  not  try  to  get  it  out  themselves, 
but  should  get  help  from  some  one  who  knows  how  to  handle 
the  ear.  In  the  middle  ear  are  three  tiny  bones.  These 
serve  as  a  bridge  to  carry  the  sound  waves  from  the  outer 
ear  into  the  inner  ear.  Waves  hit  against  the  membrane 


Parts  of  the  ear.     Notice  the  three  little  bones  in  the  middle  ear. 

and  cause  it  to  vibrate,  and  are  transferred  to  the  mid- 
dle ear.  Here  deep  in  an  opening  in  the  bone  of  the 
skull  is  an  instrument  a  thousand  times  more  delicate 
than  the  most  wonderful  piano  in  existence.  This  in- 
strument receives  the  sound  waves  and  transfers  them  to 
the  brain. 

The  ear  is  also  a  balancing  organ,  and  in  many  lower 
animals  has  this  function  only.  Our  equilibrium  is  main- 
tained by  means  of  three  so-called  semi-circular  canals 
which  are  set  into  the  opening  at  different  angles.  Those 
men  who  wish  to  become  aviators  must  have  a  perfect 


378 


INDOOR  RECREATION 


sense  of  equilibrium,  and  if  their  semi-circular  canals  are 
not  in  excellent  condition,  they  cannot  enter  this  arm  of 
government  service. 

Music  and  noise.  — We  are  all  aware  of  differences  in  the 
sounds  that  come  to  the  ear  which  cause  us  to  say,  "  This 
is  noise,"  or  "  This  is  music."  These  differences  are  due 
to  definite  pitch  relations  and  periodic  movement  of  sound 


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The  musical  scale. 

waves.  The  beating  of  a  tom-tom  and  the  monotonous 
chant  of  a  savage  in  his  war  dance  are  periodic,  and  have 
a  definite  pitch,  but  they  are  not  pleasing  to  our  ear, 
hence  they  cannot  be  classified  as  music  to  us,  although 
to  the  savage  who  makes  them  and  enjoys  them,  they  are 
music. 

The  musical  scale.  —  Our  music  is  built  up  on  a  series 
of  sounds  having  definite  ratios  of  vibration.  This  is 
called  the  musical  scale.  A  study  of  the  diagram  below 
shows  the  staff,  with  the  names  of  the  notes  or  letters 


STRINGED  INSTRUMENTS  379 

given  these  notes,  with  the  number  of  vibrations  that 
each  makes.  This  series  of  tones,  which  is  used  for  all 
kinds  of  musical  instruments  the  world  over,  is  known  as  the 
musical  scale.  Each  higher  tone  in  the  next  scale  will 
have  twice  the  vibration  rate  of  that  of  the  corresponding 
letter  in  the  scale  shown  in  the  diagram,  and  each  of  the 


An  instrument  with  many  strings.    Can  you  locate  the  strings  which  give  the  low  tones  ? 

next  lower  scale  will  have  half  the  vibration  rate  of  the 
corresponding  tone  in  the  scale  shown.  There  are  on  the 
piano  and  organ  keyboard  black  keys  which  have  inter- 
mediate rates  of  vibration.  These  are  the  so-called  sharps 
and  flats,  and  without  these  notes  modern  music  would 
be  impossible. 

Stringed  instruments   and  how  they   make   sound.  - 
We  have  already  alluded  to  the  fact  that  a  note  of  low 
pitch  is  caused  by  the  vibration  of  a  long  string,  while 


INDOOR  RECREATION 


notes  of  higher  pitch  are  caused  by  the  more  rapid  vibra- 
tion of  shorter  strings.  In  stringed  instruments,  such  as  the 
banjo,  guitar,  mandolin,  violin,  and  cello,  the  musical 
scale  is  made  by  cutting  down  the  length  of  the  string  by 
means  of  shortening  it  with  the  ringers.  In  the  case  of 
the  piano  and  harp,  the  strings  are  all  made  of  varying 
lengths,  each  producing  its  own  tone.  Just  as  we  found 
in  changing  the  shape  of  our  mouth  and  tongue  we  could 
produce  different  qualities  of  tone,  so  the  instrument 


maker  produces  different  quality  by  making  his  instru- 
ments in  different  shapes. 

The  phonograph.  —  The  phonograph  has  become  a  very 
important  part  of  our  home  life,  for  though  relatively 
few  of  us  can  make  music,  most  of  us-  enjoy  it.  The 
phonograph  is  a  musical  device  for  reproducing  sounds. 
The  original  sounds  are  recorded  as  a  fine  wavy  line  on  a 
wax  cylinder  or  plate.  The  records  we  buy  are  duplicates 
of  this  original,  or  master  record.  The  reproducing  mech- 
anism has  a  diaphragm  capable  of  very  delicate  vibra- 
tions. This  is  connected  with  a  needle  which  rests  on  the 


GOOD  READING  AND  WHAT  IT  MEANS          381 

record.  When  the  record  is  set  in  motion,  the  needle 
follows  the  fine  wavy  line  and  is  made  to  vibrate  to  cor- 
respond with  the  vibrations  of  the  original  sound  waves. 
These  vibrations  are  communicated  to  the  diaphragm,  and 
this  causes  sound  waves  in  the  air,  which  come  to  us  as 
reproductions  of  the  original  sound. 

Good  reading  and  what  it  means.  —  We  have  already  said 
that  life  is  made  up  of  bundles  of  habits.  We  form  habits 
by  doing  things  when  quite  young,  and  you  are  now  at  an 
age  when  you  can  form  them  most  easily.  Why  not  use 
some  of  the  time  you  spend  in  recreation  in  getting  the 
habit  of  reading  good  books  and  good  magazines?  Far 
too  many  boys  and  girls  limit  their  reading  to  the  daily 
newspaper  or  some  of  the  various  cheap  weekly  and 
monthly  magazines.  Life  will  be  far  richer  to  you  if  in- 
stead of  feeding  your  mind  upon  trash,  you  use  something 
which  will  be  of  use  to  you  later.  It  is  simply  a  matter 
of  habit  whether  you  read  a  number  of  poorly  written 
stories  with  very  little  of  real  interest  in  them,  or  whether 
you  form  the  habit  of  reading  books  that  are  really  worth 
while.  What  could  be  more  absorbing,  for  example,  than 
Stevenson's  "  Kidnapped  "  or  "  Treasure  Island,"  Scott's 
"  Ivanhoe,"  or  Kipling's  "  Captains  Courageous"?  Such 
books  rank  high  as  literature  and  at  the  same  time  are 
as  thrilling  as  you  may  desire.  Some  other  stories  of  in- 
terest to  boys  and  girls  are  as  follows :  Kipling's  "  Just 
So  Stories,"  and  "  Jungle  Books,"  Numbers  One  and 
Two ;  Poe's  "  The  Gold  Bug  "  ;  Carroll's  "  Alice  in  Wonder- 
land "  and  "  Through  the  Looking  Glass";  Arnold's 
"  Tom  Brown  at  Rugby  " ;  Scott's  "  Ivanhoe  "  and 
"  Guy  Mannering " ;  Dickens'  "  Tale  of  Two  Cities," 
"  Nicholas  Nickleby,"  and  "  Pickwick  Papers,"  the  latter 


382  INDOOR  RECREATION 

if  you  want  a  good  laugh ;  Lanier's  "  King  Arthur  " ; 
Pyle's  "  Robin  Hood  "  ;  Blackmore's  "  Lorna  Doone." 
For  real  fun  read  "  Uncle  Remus  "  and  "  Peterkin  Papers  "  ; 
Lear's  "  Nonsense  Rhymes,"  and  even  "  Little  Black 
Sambo."  Girls  will  enjoy  "  Peter  Pan,"  and  Barrie's 
"  Little  Minister,"  or  "  Sentimental  Tommy,"  and  we 
never  get  tired  of  stories  such  as  "  Don  Quixote  "  and 
some  of  Shakespeare's  plays.  As  for  magazines,  why  not 
make  a  rule  of  reading  articles  that  interest  you  from 
some  good  weekly  such  as  the  "  Independent  "  or  the 
"  Outlook,"  and  boys'  and  girls'  magazines  such  as  "  Youth's 
Companion,"  "  Saint  Nicholas,"  and  boy  and  girl  scout 
magazines.  Boys  will  certainly  enjoy  "  Popular  Science," 
and  "  Popular  Mechanics."  There  are  always  plenty  of 
good  monthlies  to  be  obtained  from  the  libraries  and  one 
should  get  the  habit  of  reading  the  stories  in  the  "  Cen- 
tury "  and  "  Harpers  "  rather  than  those  of  the  many 
trashy  illustrated  magazines  that  cover  our  news  stands. 
To  sum  up,  learn  to  like  good  literature  rather  than  trash, 
and  get  the  habit  of  reading  at  home. 

An  evening  at  home.  —  Have  you  ever  thought  that  the 
whole  of  society  as  we  know  it  in  this  country  and  in  all 
the  civilized  world  is  built  upon  the  family  as  a  center? 
While  this  book  has  treated  of  the  family  in  its  relation  to 
the  home,  the  next  book  will  concern  itself  with  you  and 
your  family  in  relation  to  your  neighbors,  or  what  we  call 
society.  But  society  would  be  of  little  value  were  it  not 
for  the  training  we  receive  in  our  home  life,  for  after  all, 
we  cannot  do  as  we  like  in  this  life.  We  are  not  indi- 
viduals living  alone.  Every  act  of  ours  which  is  selfish 
may  have  as  a  consequence  some  influence  over  another 
person's  life.  At  home  we  obey  mother  and  father  be- 


PUZZLES  AND   GAMES  383 

cause  we  love  them.  We  do  not  think, -perhaps,  that  the 
result  of  our  disobedience  might  bring  annoyance  or  even 
disgrace  upon  them  or  others  in  the  family,  but  such  is 
usually  the  case. 

In  our  ideal  home  father  and  mother  will  join  in  many 
of  our  social  activities.  An  evening  gathering  around 
the  dining  table,  or  perhaps  under  the  cheerful  glow  of  the 
lamp  on  the  center  table  in  the  living  room  should  be  a 
time  when  we  learn  to  enjoy  each  other's  society  through' 
conversation,  story-telling,  and  games.  Here  again  habit 
may  play  a  part.  Get  the  habit  of  telling  the  funny 
things  that  happen  to  you  during  the  day  at  school,  or  else- 
where. Let  father  and  mother  have  a  good  laugh  over 
some  of  your  pranks  or  jokes,  for  it  is  good  hygiene  to  be 
cheerful  at  the  table.  An  interesting  habit  for  the  family 
to  form  is  that  of  picking  over  some  of  the  interesting  hap- 
penings told  about  in  the  newspaper,  or  perhaps  you  have 
learned  some  new  science  facts  in  school  and  are  reading 
up  for  a  home  project.  Why  not  let  father  and  mother  know 
about  it?  They  are  sure  to  be  interested.  Sometimes  a 
good  charade  in  which  two  or  three  members  of  the  family 
act  out  some  word  by  syllables  will  be  good  fun  and  will 
sharpen  your  wits.  An  interesting  form  of  home  recreation 
is  to  try  to  act  out  some  little  story  you  have  read  with 
brothers  and  sisters. 

Puzzles  and  games.  —  Perhaps  one  of  the  best  ways 
of  spending  our  recreation  time  in  the  evening  is  in  playing 
games.  There  are  a  great  many  kinds  of  games,  arid  this 
is  not  the  place  to  tell  how  to  play  them,  but  games  of 
skill  are  certainly  the  most  fun.  Checkers,  dominoes, 
and  halma  are  all  good  games  which  train  us  to  think 
quickly,  for  they  are  an  interesting  kind  of  mental  arith- 


384  INDOOR  RECREATION 

metic.  Crokinole,  carroms,  ping  pong,  and  table  tennis, 
or  games  in  which  marbles  are  used,  and  above  all,  pool 
and  billiards,  are  interesting  games  of  skill  in  which  the 
eye  and  the  hand  play  important  parts.  Chess  is  an  in- 
teresting game,  and  one  that  requires  so  much  skill  that 
many  volumes  have  been  written  on  how  to  play  it,  and 
it  has  been  called  the  royal  game.  Jig-saw  puzzles  are 
fun  to  use  when  others  wish  to  read  and  you  have  to  play 
alone.  They  are  in  addition  easily  made,  for  any  boy 
can  afford  a  jig-saw,  and  a  jig-saw  puzzle  can  easily  be 
made  by  pasting  a  colored  picture  on  a  flat  board  and 
then  cutting  the  picture  up  into  various  patterns. 

Stamp  collecting.  —  Another  interesting  home  amuse- 
ment is  that  of  stamp  collecting.  Not  only  is  it  good 
fun  to  have  a  collection  of  stamps,  but  it  also  may  teach 
us  a  great  deal  about  the  geography,  money,  and  even 
the  history  of  the  different  countries  of  the  world.  While 
no  one  of  us  can  expect  to  have  a  very  large  collection,  yet 
it  is  quite  easy  to  begin  one,  and  you  will  soon  discover 
that  many  grown-ups  who  have  kept  their  boyhood  col- 
lections are  always  glad  to  start  the  young  collector  with 
a  present  of  a  few  stamps.  Wholesale  houses  which 
deal  with  other  countries  are  sure  to  receive  stamps,  and 
usually  they  can  be  had  for  the  asking.  One  need  not 
spend  much  money  in  ,this  pastime,  for  there  are  always 
many  other  boys  and  girls  who  will  collect  with  you, 
and  who  will  exchange  duplicate  stamps.  A  good  way 
to  enjoy  stamp  collecting  is  to  form  a  small  club  which 
meets  around  in  the  homes  of  different  boys  and  girls. 
Invite  some  older  person  who  is  interested  to  come  in  to 
your  meetings  and  show  you  his  collection.  He  will 
probably  be  glad  to  do  it,  and  will  tell  you  many  interest- 


MECHANICAL  TOYS  385 

ing  things  about  stamp  collecting  and  other  countries. 
Sometimes  you  can  have  a  stamp  auction,  or  an  exchange, 
and  thus  make  an  evening  pass  very  pleasantly  indeed. 
Be  sure,  if  you  have  been  given  an  old  collection  by  some 
relative  or  friend  collected  years  ago,  that  you  do  not  give 
away  or  sell  cheaply  the  one  or  two  valuable  stamps  that 
may  be  contained  in  the  collection.  The  best  way  to  keep 
a  collection  is  to  buy  a  cheap  blank  book  with  places  for 
the  stamps  and  to  have  a  catalog.  In  this  way  one  can 
insert  the  stamps  where  they  belong. 

Mechanical  toys.  —  Not  all  of  us  can  afford  some  of 
the  expensive  mechanical  railroad  trains,  boats,  sub- 
marines, and  airplanes  that  we  see  nowadays,  but  almost 
any  boy  can  make  a  start  by  purchasing  one  of  the 
many  erecting  devices  found  in  the  stores  to-day,  such 
as  Meccano  and  Erecto.  These  are  instructive  as  well 
as  interesting  as  toys,  because  we  can  actually  build  some 
of  the  things  that  we  see  planned  or  read  about,  and  if  we 
cannot  afford  such  toys,  a  few  simple  tools  and  a  tool  box 
will  give  us  more  real  enjoyment  than  almost  anything 
else,  for  who  does  not  like  to  make  things.  It  is  for  this 
reason  that  we  played  with  blocks  when  we  were  younger, 
and  boys  and  girls  twelve  to  fifteen  years  old  like  to  make 
things,  too.  Perhaps  it  is  dolls'  dresses,  or  it  may  be  a 
model  airplane  and  mechanical  engines  and  boats ;  these 
are  interesting  because  through  the  use  of  them  we  learn 
something  about  the  real  machines  we  shall  meet  in  later 
life.  Some  boys  have  given  to  them  year  after  year  the 
various  parts  of  a  toy  railroad,  and  in  time  will  have  tracks, 
stations,  bridges,  and  turn  tables,  block  signals,  and 
switches,  and  models  of  steam  and  electric  locomotives. 
These  boys  will  study  and  understand  the  working  and  the 

H.-WHIT.  CIV.   SCI.   IN  THE  HOME  —  2$ 


386 


INDOOR  RECREATION 


running  of  their  railway  system,  and  with  their  friends 
pass  many  happy  hours  u  running  a  railroad." 

Homemade  electricity.  —  A  great  deal  of  fun  may  be 
had  from  a  little  further  knowledge  of  electricity  which 
can  be  made  in  the  home.  You  have  sometimes  produced 
an  electric  spark  when  you  "  scuffed  "  your  feet  over  the 
carpet  in  winter  or  rubbed  the  cat's 
fur  the  wrong  way,  or  had  your  hair 
stand  up  in  an  astonishing  manner 
when  you  brushed  it.  These  are  all 
caused  by  electricity.  Many  interest- 
ing things  can  be  done  at  home  with 
this  electricity  if  the  air  is  cold  and 
dry.  If  a  hard  rubber  fountain  pen  or 
a  rubber  comb  is  rubbed  briskly  with 
flannel  it  will  attract  small  bits  of 
An  electrified  rod  repels  the  paper  or  a  pith  ball  supported  by  a 
thread.  If  the  ball  or  the  bits  of  paper 
become  electrified,  as  they  sometimes  will  after  clinging  to 
the  rubber  for  a  moment,  they  will  be  repelled  and  fly 
away  from  it. 

Experiment.  —  To  demonstrate  static  electricity. 

Materials:  Hard  rubber  rod  or  stick  of  sealing  wax.  Two  large  rods  of 
solid  glass.  Fur.  Flannel.  Silk.  Pith  ball. 

Method  and  Results:  Electrify  the  glass  (previously  warmed  a  little)  by 
nibbing  with  silk.  Support  this  on  a  wire  stirrup  supported  by  a 
thread.  Electrify  the  other  glass  rod.  Bring  the  charged  ends  near 
each  other.  Result?  Rub  the  hard  rubber  with  fur.  Bring  the  charged 
end  near  the  charged  end  of  the  suspended  glass  rod.  Result  ?  Hang  a 
pith  ball  by  a  thread.  Hold  an  electrified  glass  on  one  side  of  it  and  an 
electrified  rod  of  hard  rubber  on  the  opposite.  Result  ?  Glass  rubbed 
with  silk  is  positively  electrified.  Rubber  or  wax  rubbed  with  flannel 
or  fur  is  negatively  electrified. 

Conclusion:    What   is   the  action   between   electrified   bodies?     When 


ELECTRICAL  TOYS 


387 


a  neutral  body  touches  an  electrified  body  the  charge  distributes  itself 
over  both  bodies,  so  they  are  electrified  alike.  Explain  the  action  of 
the  pith  ball  when  held  between  the  glass  and  hard  rubber. 

Electrical  toys.  —  There  are  several  different  types  of 
toy  electric  motors.  You  will  find  it  interesting  to  examine 
some  of  them  to  see  if  you  can  recognize  the  different  types 
and  find  out  how  they  work.  A  most  interesting  home 
project  would  be  to  build  your  own  motor.  Directions 
for  this  can  be  found  in  almost  any  good  boy's  book  of 
inventions,  such  as  "  Home  Made  Toys  for  Boys  and 
Girls,"  by  A.  N.  Hall.  There  are  many  electromag- 
netic devices  from  which  one  may  get  a  lot  of  fun,  for  ex- 
ample, an  electric  hammer  can  be  made  by  winding  a  coil 
of  wire  around  a 
pencil.  Make  the 
coil  three  inches  tall, 
and  wind  about  ten 
layers  of  No.  16  in- 
sulated wire.  Re- 
move the  pencil. 
Connect  one  end  of 
the  coil  to  a  battery 
consisting  of  one  or 
more  dry  cells.  Hold 
the  coil  an  inch 

above  the  table.  Place  a  large  nail  in  the  hole  inside  the 
coil  letting  the  head  of  the  nail  rest  on  the  table.  Now 
attach  the  wire  from  the  other  end  of  the  coil  to  the  other 
pole  of  the  battery,  and  the  nail  will  rise  in  the  coil.  Break 
the  contact,  and  the  nail  will  fall,  striking  a  strong  blow  on 
the  table. 

The  use  of  electricity  in  working  a  home  telephone  or 


A  toy  electric  hammer. 


388 


INDOOR  RECREATION 


telegraph  outfit  will  be  given  when  considering  communi- 
cation in  the  next  book. 


SCORE  CARD  OF  MY  INDOOR  RECREATIONS 


Sc 

DRE 

Perfect 
Score 

My 

Score 

Piano  or  organ  

\ 

Playing  or  singing  by  members  of  the  family      .... 
Victrola  or  piano  player 

5 

Have  read  at  least  five  books  listed  in  Chapter  XXIV, 
pages  381-382      

5s 

Habitually  read  at  least  three  standard  magazines     .     . 
Talk  over  day's  experiences  and  tell  funny  stories  at  meals 
Group  games  played  in  evenings,  whole  family  taking  part 
sometimes      

5 
5 

r 

Skillful  in  at  least  two  games  mentioned  in  Chapter  XXIV 
Collect  stamps,  or  make  collections  of  other  objects; 
have  a  hobby 

5 

Have  made  at  least  one  toy  mentioned  in  Chapter  XXIV, 
or  have  completely  dressed  a  doll,  making  all  clothes 
myself  ....                                                         v 

TOTAL    

CQ 

REFERENCE  BOOKS 

Beard,  American  Boy's  Handy  Book  (For  projects).     Charles  Scribner's  Sons. 
Beard,  What  a  Girl  Can  Make  and  Do  (For  projects),  pages  227-235.     Charles 

Scribner's  Sons. 
Bedell,  Practical  Electroplating  (For  projects).     Published  by  author,  Springfield, 

Mass. 

Brownell,  General  Science,  Chapter  X.     P.  Blakiston's  Son  and  Company. 
Butler,  Household  Physics,  Chapter  IV  (Sound).     Whitcomb  and  Barrows. 
Carrington,  The  Boy's  Book  of  Magic.     Dodd,  Mead  and  Company. 
Chemistry  Sets,  Electrical  Sets,  Erector  Sets.    A.  C.  Gilbert  Company,  New  Haven, 

Connecticut. 

Chemistry  Sets,  Chemcraft.     Porter  Chemical  Company,  Hagerstown,  Maryland. 
Clark,  Introduction  to  General  Science,  Chapter  XXXI.     American  Book  Company. 
Fall,  Science  for  Beginners,  Chapter  XXIV.    World  Book  Company. 
Fisher  and  Fisk,  How  to  Live,  Chapter  IV  (For  teachers). 
Hall,  Home  Made  Toys  for  Girls  and  Boys.    Lothrop,  Lee  and  Shepard  Company. 


REFERENCE  BOOKS  389 

Hessler,  First  Year  in  Science,  Chapters  VIII  and  IX.  Benj.  Sanborn  and  Com- 
pany. 

Hodgdon,  General  Science,  Chapter  XII  (For  projects).  Hinds,  Hayden,  and 
Eldridge. 

Kelley,  Three  Hundred  Things  a  Bright  Girl  Can  Do.     Dana  Estes  and  Company. 

Lynde,  Physics  of  the  Household,  Chapters  XXVIII,  XXIX.  The  Macmillan  Com- 
pany. 

Meccano  Outfits.     Meccano  Company,  Inc.,  New  York. 

Sloane,  Electric  Toymaking  for  Amateurs  (For  home  projects).  Norman  Henley 
and  Company. 

St.  John,  Real  Electric  Toy  Making  for  Boys.     Thomas  St.  John. 

Tolman,  Hygiene  for  the  Worker,  Chapter  X.     American  Book  Company. 

Van  Buskirk  and  Smith,  The  Science  of  Everyday  Life,  Project  I.  Houghton  Mifflin 
Company. 

Williams,  How  it  Works,  pages  227-309.     Nelson  and  Company. 

Winslow,  Healthy  Living,  Chapter  XVI.     C.  E.  Merrill  and  Company. 


CHAPTER  XXV 

OUTDOOR   RECREATION 

Problems.  —  i .    To    learn   what   games    can    be    played 
in  the  home  yard. 

2.  To  find  out  what  science  principles  underlie  our  com- 
mon games  and  toys. 

3.  To  see  how  a  lens  makes  objects  appear  larger. 

4.  To  understand  how  pictures  are  taken. 

5.  To  learn  the  relation  of  our  earth  to  other  heavenly 
bodies. 

Experiments.  —  i.   Demonstrate  gyroscopic  motion  with  toy  gyroscopic 
tops. 

2.  To  show  centrifugal  force. 

3.  To  show  the  processes  of  printing,  developing,  and  fixing  a  picture. 

Project  I.  —  To  PLAN  FOR  UTILIZING  THE  PLAYGROUND   OF  THE 
HOME  LOT. 

1.  Determine  what  space  is  needed  for  games  which  interest 
you. 

2.  Which    games    require    permanent    location    because    of    the 
fixtures,  and  which  allow  the  ground  to  be  used  for  other  games 
at  times? 

3.  What  will  be  the  cost  of  the  games?    What  ones  can  you 
make  or  arrange  by  yourself? 

Suggested  Projects. 

1.  MAKE  A  PINHOLE  CAMERA  AND  TAKE  PICTURES  WITH  IT. 

2.  TAKING  AND  MAKING  PICTURES. 

390 


THE  HOME  YARD  AND  PLAYGROUND  391 

3.  TO  MAKE  A   BOX  KITE. 

4.  TO  MAKE  A  SAILBOAT  THAT  WILL  SAIL  INTO  THE  WIND. 

5.  TO  MAKE  A  TOY  AIRPLANE. 

6.  To  MAKE  A  RUSSIAN  NINEPIN  SET. 

7.  TO  LEARN  TWENTY  CONSTELLATIONS. 

The  home  yard  and  playground.  —  Fortunate  indeed 
are  the  children  who  have  a  yard  which  is  their  own  in 
which  to  play.  In  many  cities  no  such  thing  is  possible, 
and  boys  and  girls  must  share  with  others  the  public  play- 
grounds where  they  are  found.  But  every  home  yard, 
no  matter  how  tiny,  ought  to  have  some  space  devoted  to 
play.  For  little  children  a  sand  box  with  its  load  of  clean 
white  sand  gives  pleasure  the  day  long,  and  even  grown- 
ups like  to  build  miniature  roads  or  tunnels,  and  fight  battles 
with  toy  soldiers,  in  the  make-believe  land  of  the  sand  box. 
For  older  boys  and  girls,  if  there  is  not  room  for  ball, 
croquet,  or  tennis,  there  is  at  least  a  place  for  the  game 
of  quoits,  tether  ball,  or  Russian  ninepins,  even  in  the 
back  yard.  Russian  ninepins  in  partic- 
ular is  great  fun,  and  requires  a  great 
deal  of  skill.  Tops  and  marbles  have 
been  played  by  generations  of  small  boys, 
yet  never  lose  their  interest.  The  top  is 
also  of  scientific  interest  to  us,  for  it 
represents  what  is  known  as  gyroscopic 
motion.  As  the  top  spins,  it  resists  the 
force  of  gravity.  As  you  doubtless 
know,  the  instrument  called  the  gyro-  The  gyroscope. 
scope  is  used  in  many  ways,  especially 
on  large  ships  to  prevent  rolling  in  storms,  in  airplanes 
to  keep  them  upright,  and  in  the  new  type  of  marine 
compass. 


392  OUTEOOR   RECREATION 

Experiment.  —  To  demonstrate  gyroscopic  motions. 

Materials:  A  toy  gyroscope. 

Method  and  Results:  Set  the  wheel  in  motion.  How  long  will  it  spin 
with  vertical  axis?  Set  in  motion  and  rest  one  end  of  axis  on  the 
wooden  support,  with  a  horizontal  axis.  If  the  wheel  were  not  spinning 
would  it  stay  in  that  position?  Set  in  motion  again.  Take  hold  of 
one  end  of  axis  and  quickly  change  from  vertical  to  horizontal.  Com- 
pare the  resistance  to  this  movement  when  the  wheel  is  revolving  to 
that  when  the  wheel  is  still. 

Conclusion:  What  are  some  laws  of  gyroscopic  action  suggested  by  these 
experiments?  How  can  the  gyroscope  act  as  a  stabilizer  of  ships  and 
airplanes  ? 

Darts,  slings,  and  bows  and  arrows.  —  Any  toy  that 
can  be  made  is  of  more  interest  than  one  we  buy,  and 
toys  which  allow  us  to  play  in  competition  with  others 
so  that  our  skill  is  matched  against  that  of  the  other 
fellow,  are  most  interesting  of  all.  Long  years  ago 
dwellers  on  the  earth  used  the  sling,  the  dart,  and  bow 
and  arrow  as  a  means  of  getting  their  food  as  well  as 
weapons  for  offense  and  defense.  We  all  know  the  story 
of  David  and  Goliath,  and  who  has  not  read  of  the  early 
days  in  this  country  when  Indians  not  only  shot  their  food, 
but  also  killed  their  enemies  with  a  bow  and  arrow  ?  Very 
briefly  some  of  the  science  underlying  their  use  may  be 
mentioned  here.  For  example,  in  the  dart,  or  in  the  arrow, 
why  do  we  have  pointed  tip,  and  feathers  or  pieces  of  stiff 
paper  at  the  hind  end  of  the  dart  or  arrow  ?  The  elasticity 
of  wood,  metal,  and  cord  is  also  strongly  shown  in  the  case 
of  the  bow.  In  the  use  of  the  sling,  when  we  whirl  the  sling 
round  and  round  before  releasing  the  missile,  we  have  a  good 
example  of  centrifugal  force.  This  is  the  force  which  would 
cause  each  one  of  us  to  fly  off  the  surface  of  the  earth  as  it 
goes  whirling  around  in  space  were  it  not  for  an  opposing 
force  which  holds  us  down,  the  force  we  call  gravity. 


PINWHEELS,  KITES,  AND   SAILBOATS 


393 


Experiment. — To  show  centrifugal  force. 

Materials:  Pail  half  full  of  water.     A  ball  fastened  to  end  of  string. 

Method  and  Results:  (a)  Swing  the  pail  of  water  rapidly  overhead  in  a 
large  circle.  Is  there  a  time  when  there  is  no  support  under  the  water? 
Does  it  fall  out  ?  (&)  Whirl  the  ball  on  the  string.  In  what  directions 
may  it  go  if  you  release  it  when  the  string  is  horizontal?  When  ver- 
tical? Make  diagrams. 

Conclusion:  Centrifugal  force  is  that  force  causing  all  bodies  moving  in 
a  curved  path  to  pull  away  from  that  path  and  to  go  off  in  a 
straight  line.  The  force  which  pulls  towards  the  center  and  keeps 
the  whirling  body  in  the  curved  path  is  called  centripetal  force.  Ex- 
plain these  terms  by  reference  to  the  above  experiments  just  performed. 


lifting  jo 


Pin  wheels,  kites, 
and  sailboats.  —  An- 
other common  toy  is 
the  pinwheel.  Most 
of  us  know  how 
to  cut  the  pinwheel, 
and  probably  every- 
body in  the  class 
knows  that  the  pin- 
wheel  revolves  by 
the  force  of  the  air 
striking  against  it, 
causing  motion.  The 
difficult  thing  in  kite 
flying  is  to  adjust  the 
cord  at  the  point  of 
attachment  so  that 
the  kite  balances  and 
w!ll  go  up  readily. 
Here  again  we  use 
the  force  of  moving  air,  and  by  fastening  the  kite  at 
an  angle  to  the  direction  of  the  wind,  we  cause  it  to  rise 


Notice  that  the  wind  produces  a  greater  lifting  force 
in  A  than  in  B,  but  that  in  B  the  greater  part  of  the 
force  of  the  wind  causes  horizontal  drifting.  This 
results  from  the  angular  adjustment  of  the  kite 
surface. 


394 


OUTDOOR   RECREATION 


When  sailing  into  the  wind,  observe  that  only  a  part  of  the  wind  force  presses  on  the 
sail  and  that  only  a  part  of  the  wind  pressure  on  the  sail  produces  a  forward  push 
on  the  boat. 

higher  in  the  air.  A  much  more  efficient  kind  is  the  box 
kite,  with  its  double  surface.  This,  as  we  can  readily  see, 
was  the  forerunner  of  the  glider,  which  in  turn  preceded 
the  airplane  of  the  present  day.  Sailboats  also  make 

use  of  the  force  of  the  wind 
against  the  sails.  An  interest- 
ing project  would  be  to  work 
out  the  reason  why  it  is  pos- 
sible to  make  a  boat  sail 
against  the  wind. 

The  simple  microscope.  — 
If  you  hold  a  double  convex 
lens  over  a  small  object  such 
as  an  insect  or  a  bug,  the 
object  appears  larger  than  it 
really  is.  The  reading  glass 
is  a  simple  microscope  consist- 
ing of  a  convex  lens.  We  can 
even  make  one  ourselves  by 
A  simple  microscope.  blowing  a  small  bulb  at  the 


\SmoJl  insect 


THE   COMPOUND   MICROSCOPE 


395 


end  of  a  piece  of  glass  tubing,  filling  this  bulb  with 
water,  and  plugging  the  end.  This  is  a  crude  micro- 
scope. 

The  compound  microscope.  —  The  compound  microscope 
is  a  large,  more  complex  structure.  As  the  diagram  shows, 
it  has  two  sets  of  lenses,  which  make  the  object  look  larger 
by  a  double  magnification,  first,  by  a  glass  nearer  the  object, 


The  compound  microscope  makes  an  image  A'B'  nearer  the  eye  than  the  object  AB 
and  then  magnifies  it  to  a  still  larger  image  ab. 

or  the  objective,  and  later  by  a  glass  nearer  the  eye,  or  the 
eyepiece.  While  not  every  boy  and  girl  can  have  a  mi- 
croscope of  his  own,  still  in  most  schools  you  will  find  a 
good  compound  microscope,  and  any  good-natured  science 
teacher  will  allow  you  to  work  out  a  project  on  the  con- 
struction and  use  of  the  compound  microscope.  All 
sorts  of  new  wonders  are  opened  to  those  of  us  who  can 
buy  a  small  microscope  for  our  own,  as  the  beautiful 
forms  of  the  snow  crystals,  the  life  in  a  drop  of  water,  the 
structure  of  an  insect's  wings.  Thousands  of  wonderful 


396 


OUTDOOR   RECREATION 


Picture  of  a  bare  house. 


objects  lie  unexplored  at  our  doors,  and  can  only  be  dis- 
covered by  means  of  this  wonderful  instrument.  Per- 
haps some  day,  when 
you  study  biology,  you 
will  learn  more  about  it 
and  its  uses. 

Photography.  —  Prob- 
ably one  of  the  most  fas- 
cinating hobbies  that 
any  boy  or  girl  can  have 
is  that  of  photography. 
Not  only  does  it  help  us 
to  understand  the  prac- 
tical use  of  the  camera 
and  its  accessories,  but 
it  also  helps  us  to  un- 
derstand better  the  ar- 
tistic value  of  objects 
in  nature.  The  accom- 
panying pictures  of  a 
farmhouse  illustrate 
very  well  what  is  meant 
by  composition  and  bal- 
ance. A  close  view 
(No.  i)  shows  the 
house  without  grounds 
or  shrubbery.  It  is  an 
example  of  poor  com- 
position although  it  has 
good  balance  of  strong 
light  and  strong  dark. 

viewpoint. 


2.   The  same  house  with  a  setting  of  grounds 
and  foliage. 


A  PINHOLE   CAMERA 


397 


picture  than  the  first.  The  house  at  the  left  is  balanced 
by  the  road  leading  to  the  right,  but  as  no  particular 
object  of  interest  is  shown  at  the  right  the  picture  has 
poor  composition.  In  the  third  picture  the  garden  path 
with  its  border  of  shrubs  and  flowers  leads  you  un- 
consciously right  to  the  door  of  the  house.  There  is 
balance  of  strong  light  and  strong  dark  with  intermedi- 
ate tones  as  well.  By  making  a  study  of  photographs 
you  can  easily  learn  what  it  is  that  gives  them  artistic 
value.  Photography  gives  us  a  new  interest  in  that 
We  can  picture  for  all  time  birds,  wild  animals,  and  our 


Explain  why  the  image  is  inverted. 

favorite  haunts  in  nature.  We  can  make  mementoes  of 
good  times  together  with  our  friends,  and  what  makes 
a  better  Christmas  present  than  a  card  which  brings  up 
some  pleasant  memory  of  summer  doings  ?  You  can  use 
photographs  to  illustrate  your  science  notebooks  instead 
of  drawings,  if  you  so  desire,  and  many  a  boy  and  girl 
have  made  the  cost  of  the  camera  several  times  over  by 
taking  photographs  and  selling  them. 

A  pinhole  camera.  —  The  simplest  camera  is  one  which 
any  ten-year-old  boy  or  girl  can  easily  make.  It  is  a  box 
of  any  convenient  size,  say  about  five  inches  square  and 
three  inches  deep.  It  must  have  a  cover  which  slides 
down  over  the  box  for  a  depth  of  at  least  one  inch.  The 


398  OUTDOOR  RECREATION 

interior  must  be  painted  black,  and  absolutely  light  tight-. 
By  following  these  directions  you  can  make  a  good  camera. 

Cut  a  hole  one  half  inch  in  diameter  in  the  middle  of  one  side  or  end 
of  the  box.  On  the  inside  of  the  box  paste  over  the  hole  a  piece  of  tinfoil. 
In  this  tinfoil  you  will  make  your  pinhole.  The  success  of  your  picture 
depends  on  the  care  with  which  you  make  this  hole.  The  best  results  are 
obtained  when  the  diameter  of  the  pinhole  is  in  proportion  to  the  square 
root  of  the  distance  from  the  pinhole  to  the  plate.1  Paste  cardboard  strips 
on  the  inside  of  cover  to  hold  the  sensitized  plate. 

The  exposure,  depending  on  the  light,  should  be  from 
ten  to  twenty  minutes.  The  picture  is  made  on  a  glass 
plate  which  is  held  in  place  by  narrow  strips  of  cardboard 
glued  in  along  the  vertical  edges  of  the  plate.  This  plate 
is  to  be  put  into  the  camera  while  in  a  dark  room.  Of 
course,  the  pinhole  should  be  kept  covered  until  you  reach 
the  object  you  wish  to  photograph  and  covered  again  after 
the  picture  is  taken. 

Camera  lenses  and  their  use.  —  There  are  two  types 
of  lenses  used,  a  single  lens,  found  in  most  cheap  cameras, 
and  a  lens  tube  with  a  double  combination  of  glasses  in 
it  which  may  be  of  long  focus.  There  is  also  a  wide  angle 
lens  of  short  focus,  which  is  excellent  for  working  indoors. 
We  also  have  the  telephoto  lens,  which  is  used  for  long 
distance  work,  and  is  excellent  for  photographing  birds, 
and  other  forms  of  wild  life. 

1  Use  the  following  formula : 

Diameter  of  pinhole  =K^  Distance  of  plate  from  pinhole 
K=     .0008 

This  diameter  may  be  measured  by  some  machinist  or  science  instructor  who  has  a  microm- 
eter caliper,  who  can  measure  a  needle  of  the  right  diameter,  so  you  can  make  the  hole  just 
the  size  of  the  needle. 

Having  obtained  a  needle  of  the  right  diameter,  do  not  force  it  all  at  once  into  the  tinfoil, 
but  work  it  slowly,  putting  pressure  first  on  the  one  side,  and  then  on  the  other  so  as  not  to 
stretch  the  foil  when  pushing  the  needle  into  the  hole.  When  you  have  made  the  hole,  be 
sure  to  smooth  off  the  edges,  as  a  clear  picture  cannot  be  made  unless  you  have  a  clean  cut 


WHAT  IS  A  NEGATIVE? 


399 


What  is  a  negative  ?  —  The  picture  is  taken  upon  a  glass 
plate  or  celluloid  film  covered  with  a  coating  of  gelatine 
and  silver  bromide,  or  some  other  silver  salt.  Light  falling 
on  this  silver  compound  causes  a  change  in  its  composition, 


Which  of  these  two  pictures  is  the  negative  ?     Which  the  positive  ? 

so  that  when  it  is  put  into  a  developer  containing  certain 
chemicals  which  complete  the  change  and  make  it  perma- 
nent, we  have  a  negative  as  a  result.  This  negative  gives 
the  light  values  in  black  and  white,  but  just  the  opposite  of 
what  they  were  in  the  objects  photographed  and  just  the  op- 
posite of  what  we  have  in  a  positive,  or  completed  print.  A 
study  of  the  accompanying  figure  will  show  this  very  clearly. 


400  OUTDOOR  RECREATION 

Experiment.  To  show  the  processes  of  printing,  developing,  and  fixing 
a  picture. 

Materials:  Three  small  glass  or  enamel  trays.  One  large  tray.  Printing 
frame  with  glass.  Film  or  glass  negatives.  Azo  or  Velox  paper.  De- 
veloping powders  and  hypo.  A  ruby  light  or  dimly  lighted  room.  A 
strong  light  for  printing. 

Method:  Work  with  some  one  who  is  experienced  in  making  pictures  at 
first.  Learn  from  him  how  to  do  the  various  operations.  Write 
a  complete  report  of  the  processes  and  the  reasons  for  them  as  learned 
from  study.  Mount  a  specimen  print  which  you  make  yourself. 


How  to  make  a  picture.  —  In  taking  a  picture,  we  should 
bear  in  mind  the  following  points :  (i)  We  wish  to  have  a 
pleasing  composition.  Try  to  get  good  balance  in  your 
picture.  Focus  on  the  principal  thing  to  be  photographed. 

(2)  Have  good  light,  and  if  possible,  have  the  light  come 
from  behind  the  camera.     Do  not  have  much  light  and 
shadow,  except  in  landscapes.     Do  not  take  a  picture  di- 
rectly in  the  sun  unless  you  shade  the  lens  of  the  camera. 

(3)  Be  sure  that  the  opening  in  your  lens  is  the  right  size 
for  the  amount  of  light.     This  is  easily  determined  by  a 
study  of  the  directions  that  come  with  any  camera.     You 
will  learn  to  know  your  own  lens  and  how  to  use  it  after 
you  have  worked  with  it  for  a  time.     (4)  Be  sure  that  you 
use  an  unexposed  plate  or  film.     Many  pictures  are  spoiled 
by  double  exposures.     The  best  way  is  to  write  on  your 
plate  holder  or  film  each  time  when  you  take  a  picture. 
(5)  Be  sure  to  make  an  exposure  of  the  proper  length. 
Too  long  an  exposure  is  as  bad  as  too  short  an  exposure. 
The  camera  must  not  be  allowed  to  move,  even  in  the  in- 
stantaneous  exposure.     If   you   take  a  snapshot  be  sure 
that  the  image  of  the  object  you  wish  to  take  is  in  the 
finder  when  you  snap  the  shutter. 

Printing.  —  Boys  and  girls  should  learn  to  print  their 


OTHER  USES  OF  LENSES  401 

own  pictures  rather  than  send  them  to  a  photographer, 
for  it  is  easy,  and  a  fascinating  pastime.  Papers  are  of  two 
types,  those  printed  by  artificial  light  and  those  printed 
by  sunlight;  the  latter  require  more  time  and  a  dark 
room.  Blue  printing  paper  is  one  form  of  sun  printing 
paper,  which  is  much  cheaper  and  easier  to  handle,  since 
we  merely  have  to  print  from  a  negative,  and  then  wash 
in  cold  water.  Chemicals  for  printing  and  developing  can 
be  found  in  any  good  photographic  shop  and  directions  for 
their  use  in  any  good  manual. 

Enlarging.  —  If  you  have  a  particularly  good  picture, 
you  may  wish  to  enlarge  it.  This  can  be  done  by  mak- 
ing a  positive  image  or  picture  by  allowing  rays  of  light  to 
pass  through  a  negative,  then  through  a  lens  which  is 
focused  on  a  sheet  of  sensitive  bromide  paper.  The  size 
of  the  enlargement  will  depend  on  the  distance  of  the  lens 
from  the  sheet.  It  is  not  difficult  to  enlarge  if  one  has  a 
room  which  can  be  darkened,  and  has  a  little  ingenuity 
so  that  he  can  make  a  frame  to  hold  the  bromide  paper. 
Enlargements  are  much  more  artistic  because  of  their 
softer  tone,  and  make  excellent  presents. 

Other  uses  of  lenses.  —  We  are  all  familiar  with  the  use 
of  the  opera  glass  and  field  glass.  A  good  pair  of  field 
glasses  apparently  decreases  the  distance  of  the  object 
looked  at  to  one  eighth  of  the  real  distance.  A  four-inch 
telescope  may  make  an  object  appear  one  three-hun- 
dredth of  its  distance.  In  the  telescope,  one  lens  is  used 
to  make  an  image  of  the  distant  object,  and  the  second 
lens,  the  eyepiece,  is  used  as  a  simple  microscope  which 
magnifies  this  image.  If  you  can  get  the  use  of  a  good 
field  glass  or  small  telescope,  look  at  the  moon  in  its  differ- 
ent phases.  You  will  find  it  a  most  interesting  object  for 

H.-WHIT.   CIV.    SCI.    IN   THE   HOME  —  26 


4O2 


OUTDOOR  RECREATION 


observation.     An  evening  with   the   telescope  is   an  ex- 
perience that  few  boys  and  girls  will  forget. 

The   stars.  —  Even   without   a   telescope,    the   heavens 
present  a  wonderful  opportunity  for  observation  to  those 

who  are  interested  in  the 
distant  parts  of  our  uni- 
verse. A  glance  at  the 
sky  makes  one  think  he 
can  see  myriads  of  stars, 
but  in  reality,  on  an 
average  one  can  rarely 
see  more  than  from  two 
to  three  thousand  stars 
while  standing  in  one 
place,  but  by  the  use  of 
a  large  telescope,  mil- 
lions of  stars  are  found. 
Astronomers  tell  us  that 
each  one  of  these  stars 
is  like  our  sun,  a  huge, 
white-hot  ball,  and  that 
many  of  them  are  very 
much  larger  than  our 

Yerkes  telescope  of  University  of  Chicago,  one  mi 

of  the  largest  in  the  United  States.  SUn.      They  appear  Very 

tiny    because    of    their 

great  distance.  When  we  realize  that  the  nearest  of 
these  stars  (Alpha  Centauri)  is  25,000,000,000,000  miles 
away,  so  far  that  it  takes  about  four  and  one  third 
years  for  its  light  to  reach  us,  we  are  lost  in  wonderment. 
And  when  we  also  know  that  another  star  (Arcturus) 
is  950,000,000,000,000  miles'  away,  and  that  it  takes  one 
hundred  sixty  years  for  its  light  to  reach  us,  we  are 


THE  LARGE  DIPPER 


403 


still  more  amazed.  It  will  help  you  to  get  some  idea 
of  the  velocity  of  light  when  you  think  that  as  you  have 
taken  five  steps  across  an  ordinary  room,  light  has  traveled 
a  distance  equal  to  about  twenty  times  the  circumference 
of  the  earth. 

The  North  Star.  —  One  star  which  has  guided  many 
travelers  is  the  North  Polar  Star  (Polaris).  When  we  see 
it,  let  us  remember  that  the  light  which  enters  our  eyes 
left  that  star  about  forty-seven  years  ago.  Since  this 
star  is  practically  in  line  with  the  axis  of  the  earth,  and 
all  other  stars  keep  the  same  relative  positions,  with  re- 
spect to  the  North  Star,  there  is  during  the  rotation  of  the 
earth  each  twenty-four  hours  an  apparent  rotation  of  all 
of  the  other  stars  in  the  sky  about  Polaris  as  a  center. 
This  fact  makes  it  of  exceptional  value  to  the  traveler. 

The  Large  Dipper.  —  One  of  the  most  conspicuous  star 
groups  or  constellations  is  the  Large  Dipper,  or  Great 
Bear,  as  it  is  sometimes 
called.  If  you  are  just 
learning  to  locate  some 
of  the  more  prominent 
stars  and  star  groups, 
the  Great  Dipper  is  one 
you  should  locate  first. 
From  that  you  can  find 
the  North  Star  (Polaris) 
and  then  work  out  to 
other  groups.  If  you  will 
examine  the  diagram, 

you  will  find  that  a  line  drawn  from  the  two  stars  at  the 
end  of  the  Dipper  points  directly  toward  Polaris,  hence, 
they  are  called  the  "  Pointers." 


Which  two  stars  are  the  "  Pointers"? 


404  OUTDOOR  RECREATION 

Other  star  groups.  —  Polaris  is  the  end  star  in  the 
handle  of  the  Little  Dipper,  or  Small  Bear.  This  can 
easily  be  found.  Except  in  the  region  very  near  the 
North  Star,  some  stars  will  be  visible  at  certain  hours 
of  the  night  and  not  visible  at  others.  It  is  an  excel- 
lent plan  to  get  some  older  person  to  show  you  how  to 
use  a  star  map,  and  then  try  to  see  how  many  new  con- 
stellations you  can  identify.  The  "  Guide  to  Nature  " 
and  the  "  Scientific  American  "  have  a  star  map  each 
month,  which  will  show  you  the  tune  of  evening  to  look 
for  certain  constellations.  No  more  fascinating  study  can 
be  found  than  that  of  elementary  astronomy,  and  learn- 
ing to  know  the  constellations  will  give  you  a  start  in 
astronomy. 

Our  relation  to  the  stars.  —  You  have  obtained  in  your 
geography  some  knowledge  of  the  relation  of  our  earth 
to  the  other  heavenly  bodies.  You  remember  that  there 
are  eight  of  these  bodies  which  travel  around  the  sun, 
the  earth  being  one  of  the  eight.  These  bodies  are  called 
planets.  They  do  not  give  out  light  of  their  own,  but 
they  do  reflect  sunlight,  and  appear  as  brilliant  stars. 
They  are  never  visible  except  in  morning  or  evening,  and 
are  therefore  called  morning  stars  and  evening  stars.  As 
we  have  just  learned,  they  are  not  true  stars,  because 
true  stars  shine  by  their  own  light.  The  names  of  these 
planets,  in  order  according  to  their  nearness  to  the  sun, 
and  the  length  of  their  year  (or  the  time  to  go  around  the 
sun) ,  are  shown  in  the  following  table : 

Mercury 88  days  Jupiter    ......  12  years 

Venus *.  225    "       ,     Saturn 29     " 

Earth 365    '  Uranus 84 

Mars 687    "  Neptune 165     " 


SHOOTING  STARS  405 

Some  of  these  planets,  such  as  the  Earth,  Jupiter,  and 
Mars,  have  moons  which  in  turn  revolve  around  them. 
These  simply  reflect  sunlight,  and  do  not  give  any  light 
themselves.  All  of  these  moons,  planets,  and  the  sun  to- 
gether make  up  a  small  heavenly  group  which  we  call  the 
Solar  System.  You  may  think  the  word  small  used  inad- 
visedly. It  is  a  large 
system  when  com- 
pared with  the  size 
of  the  earth,  but 
compared  with  the 
size  of  the  other 
systems  and  the  vast 
expanse  of  the  uni- 
verse which  we  look 
into  on  a  clear  night, 
it  is  absolutely  insig- 
nificant. It  is  rea- 
sonable to  believe 
that  each  of  the  mil  - 

Relative  sizes  of  planets,  sun,  and  moon. 

lions  of  stars  in  the 

sky  has  its  own  family  of  planets  and  moons,  just  as  our 
sun  has,  but  since  these  are  so  far  away  and  have  no  light 
of  their  own,  they  are  invisible  to  us. 

Shooting  stars.  —  We  have  all  seen  the  burst  of  stars 
which  comes  from  the  explosion  of  a  beautiful  rocket, 
and  indeed  we  have  sometimes  mistaken  the  light  from 
a  small  toy  balloon  for  that  of  a  star.  It  is  not  strange 
that  some  people  have  been  deceived  by  so-called  "  shoot- 
ing stars  "  and  thought  that  stars  were  actually  falling. 
Such,  however,  is  not  the  case.  There  are  throughout 
the  space  which  surrounds  the  earth  and  other  planets 


406  OUTDOOR  RECREATION 

countless  numbers  of  small  bodies  which  are  moving  at  a 
speed  almost  one  hundred  times  as  swift  as  that  of  a  rifle 
bullet,  but  since  there  is  no  air,  there  is  no  resistance  to 
these  bodies,  and  they  cannot  be  seen.  If  any  of  them 

going  at  this  rate  of 
speed  reach  the  upper 
air  they  become  hot  be- 
cause of  the  friction  and 
soon  begin  to  glow  so 
that  they  appear  as  ob- 
jects which  are  on  fire. 

A  shooting  star.  g-^    ^   ^^    attracts 

them,  they  fall  toward  it,  usually  reaching  the  earth  as  dust. 
Sometimes,  however,  a  very  large  meteor  plunges  into  the 
earth,  and  when  we  dig  it  up,  we  find  it  to  be  a  mass  of 
rock  looking  not  unlike  iron. 

Home  and  community,  —  All  through  the  book  we  have 
tried  to  show  how  science  touches  pur  everyday  life.  Only 
a  few  of  the  many  home  pleasures  have  been  suggested  here, 
for  much  of  your  pleasure  will  be  had  in  the  companionship 
of  others.  Hiking,  fishing,  insect  collecting,  camping, 
boating,  and  bathing  are  all  pleasures  that  others  must 
share  with  you  to  be  really  fun.  So  we  will  leave  the 
discussion  of  these  to  your  project  making  and  to  the  later 
treatment  of  community  life.  The  purpose  of  the  next  book 
will  be  to  show  you  how  intimately  science  is  connected 
with  the  lives  of  those  who  live  together  as  citizens  in  the 
community.  It  is  hoped  that  the  book  just  being  finished 
may  help  to  make  you  better  and  more  useful  members 
of  your  own  family.  The  next  book  will  help  to  make 
you  more  useful  and  efficient  citizens  in  your  own  com- 
munity. 


SCORE   CARDS 


407 


The    last   score   card.  —  After  you   have   finished   this 
card  you  are  to  take  all  of  the  completed  cards  and  copy 

SCORE  CARD  OF  OUTDOOR  RECREATIONS  (FOR  GIRLS) 


Sot 

)RE 

Perfect 
Score 

My 

Score 

Have  set  up  (5)  and  can  play  well  (5)  one  of  the  games 
mentioned  in  Chapter  XXV      
Can  play  well  tennis,  croquet,  or  beanbags     
Collect  flowers  and  can  identify  at  least  20  varieties  .     . 
Collect  insects  and  have  specimens  of  at  least  six  orders  . 
Make  photographs  (5),  develop  and  print  my  own  pictures 
M 

IO 
5 

10 

5 

IO 

Belong  to  Hiking  Club  or  Girl  Scouts  —  can  walk  at  least 
ten  miles  in  a  day  without  feeling  tired     
Can  pick  out  North  Star  and  identify  at  least  three  con- 
stellations           

5 
5 

TOTAL 

^o 

SCORE  CARD  OF  OUTDOOR  RECREATIONS  (FOR  BOYS) 


So 

)RE 

Perfect 
Score 

My 
Score 

Have  set  out  (5)  and  can  play  well  (5)  at  least  one  game 
mentioned  in  Chapter  XXV      

IO 

Have  made  a  kite  that  will  fly  and  stay  up  in  a  moderate 
wind  or 
Have  made  a  model  airplane  that  will  fly  at  least  100  feet 
Have  made  a  sailboat  that  will  sail  against  the  wind     . 
Collect  insects  and  have  specimens  of  at  least  six  orders  . 
Make  photographs  (5),  develop  and  print  my  own  pictures 

(•>) 

10 

5 
5 

IO 

Belong  to  Hiking  Club  or  Boy  Scouts,  can  walk  at  least 
twenty  miles  a  day  without  feeling  tired     
Can  pick  out  North  Star  and  identify  at  least  three  con- 
stellations            

5 
5 

TOTAL    

50 

408  OUTDOOR    RECREATION 

in  the  column  marked  "  My  final  real  score  "  in  the  long 
preliminary  score  card,  the  totals  for  each  of  the  smaller 
cards  at  the  ends  of  certain  of  the  chapters.  It  will  be 
interesting  to  compare  your  final  score  with  the  guess 
you  made  at  the  beginning.  Were  you  too  high  in  your 
first  estimate  ?  And  do  you  really  think  you  have  improved 
conditions  somewhat  as  a  result  of  this  study  of  science? 
If  so,  then  this  book  will  have  accomplished  its  purpose. 

REFERENCE  BOOKS 

Adams,  Harper's  Outdoor  Handy  Book,  pages  1 20-143  (Kites) .     Harper  and  Brothers. 

Baker,  Boy's  First  and  Second  Books  of  Inventions.    McClure,  Phillips,  and  Company. 

Beard,  Outdoor  Handy  Book,  pages  46-94  (Kites).     Charles  "Scribner's  Sons. 

Book  of  Knowledge,  Project  References  for  all  above. 

Bodmer,  Book  of  Wonders.     Project  references.     Presbrey  Syndicate. 

Ball,  Starland  (Last  chapter,  although  entire  book  is  interesting  reading).  Ginn 
and  Company. 

Campbell,  American  Girl's  Home  Book  of  Work  and  Play,  pages  175-183  (Archery). 
G.  P.  Putnam  and  Sons. 

Cassell,  Complete  Book  of  Sports  and  Pastimes,  pages  239-244.  Cassell  and  Com- 
pany. 

Clark,  Introduction  to  Science,  Chapter  XXVIII  (Photography).  American  Book 
Company. 

Downing,  A  Field  and  Laboratory  Guide  in  Physical  Nature-study.  University  of 
Chicago  Press. 

Fall,  Science  for  Beginners,  Chapter  XXVIII.     World  Book  Company. 

Hodgdon,  Elementary  General  Science,  Chapter  XII  (Stars,  etc.).  Hinds,  Hay  den, 
and  Eldridge. 

How  to  Make  Good  Pictures.     Eastman  Kodak  Company,  Rochester,  N.  Y. 

Lynde,  Physics  of  the  Household,  Chapter  XXVI.     The  Macmillan  Company. 

Miller,  Outdoor  Sports.     Doubleday,  Page  and  Company. 

Miller,  Outdoor  Work.     Doubleday,  Page  and  Company. 

Smith  and  Jewett,  Introduction  to  Science.     The  Macmillan  Company. 

Thompson,  Boy's  Book  of  Sports,  pages  177-196.    The  Century  Company. 


INDEX 

NOTE.  —  Numbers  in  heavy-faced  type  refer  to  pages  containing  illustrations  as  well  as 
descriptive  text. 


Abdomen  of  insect,  319 
Absorbing  organs,  in  animals,  100 

of  plants,  304 
Accommodation,  259 

relation  to  focusing,  259 
Acids,  test  for,  234 
Adenoids,  70 
Aerobic,  153 
Air,  in  lungs,  63 

impurities  in,  46 

ocean  of,  40 

pressure,  59 

principal  gases  in,  42 

properties  of,  42 

pure,  27 

reality  of,  41 

relation  to  health,  65,  163 

relation  to  light,  184 

relation  to  soil,  301 

supply,  regulation  of,  193 

weight  of,  59 

Air  passages,  diseases  of,  70 
Ammeter,  364 
Ampere,  364 
Anaerobic,  153 
Anopheles,  14,  135 
Ants,  138 

relation  to  food,  139 
Arsenate  of  lead,  326 
Arteries,  145 
Astigmatism,  260 

Bacteria,  19,  59 
aerobic,  153 
anaerobic,  153 
bacillus,  153 
coccus,  153 
conditions  favorable  and  unfavoiable, 

119 
culture  medium,  67 


Bacteria  —  Continued 

denitrifying,  316 

growth  of,  119,  159 

relation  to  diseases,  160 

relation  to  food,  120 

relation  to  soil,  316 

types  of,  1 60 
Bathroom,  modern,  148,  281 

flush  tank,  150 
Bedbugs,  138 

Bedroom,  ideal,  ventilation  of,  277 
Bees  and  wasps  (Hymenoptera),  descrip- 
tion of,  323 

Beetles  (Coleoptsra),  description  of,  323 
Bell,  electric,  351 
Bifocal  lens,  261 
Birds,  328,  329 

Bleaching,  relation  to  clothes,  233 
Blood  vessel,  145,  220 
Body,  compared  to  engine,  91 

composition  of,  92 

poisons,  1 66 

relation  to  clothing,  220 

relation  to  food,  92,  99 

relation  to  heat,  221 
Bordeaux  mixture,  326 
Bread  making,  118 

yeasts  in,  117 
Breathing,  60 

necessity  for,  63 

process  of,  61 
Brick,  making  of,  273 
Bronchial  tubes,'  60 
Bugs  (Hemiptera),  description  of,  323 
Burning  test,  228 
Butterfly  or  moth,  adult  or  imago,  320 

eggs,  319 

larva  or  caterpillar,  320 

life  history  of,  319 

pupa,  320 


409 


4io 


INDEX 


Calorie,  99 

Camera,  255,  397 

Candle,  relation  to  air,  44 

Canning  foods,  124 

Capillaries,  146 

Capillarity,  experiment  in,  gravel,  sand, 

clay,  and  loam,  300 
Carbohydrates,  94 

test  for,  95 

Carbon,  93,  176,  179,  361 
Carbon  dioxide,  43 

fire  extinguisher,  215 
Carbon  tetrachloride  extinguishers,  rela- 
tion to  fire,  213 
Carelessness,  31 
Carpet  beetles,  139 

destruction  of,  139 
Caterpillar,  320 
Caves,  formation  of,  86 
Cellar,  282 

relation  to  heat,  282 
Cells,  48 

electric,  dry,  361 
joining  of,  365 
life  of,  366 
to  make,  362 
wet,  361 

in  body,  47 

respiration,  62 

Centrifugal  force,  demonstration  of,  395 
Cesspool,  153 
Chemical  elements,  93 
Chemical  extinguishers,  types,  213 

section  of,  215 
Choroid,  258 
Chrysalis,  320 
Ciliary,  259 

Cinders,  removal  of,  265 
Cisterns,  77 
Cleanliness,  habits  of,  169 

relation  to  clothes,  232 

relation  to  home  life,  31 
Clothing,  220 

attacked  by  insect,  139 

care  of,  232 

frauds  in,  231 

origin  of,  225 

relation  to  cold,  220 

use  of,  223 

Coal  beds  in  the  earth,  176 
Coal  stove,  190 
Cockroaches,  138 


Cocoon,  320 

Cold,  relation  to  clothing,  220 

Cold  frame,  309 

Cold  storage  warehouse,  121 

Color,  256 

in  the  home,  276 

nature  of,  256 
Color  blindness,  264 
Combustion,  46 

Commercial  motors,  in  the  home,  35  2 
Concrete  skyscraper,  272 
Conduction,  186 
Convection  currents,  184,  185 

caused  by  hot  stove,  191 
Cooking,  methods  of,  in,  112 

relation  to  food,  109 

use  of  heat  in,  198 
Cootie,  139 
Corn  smut,  317 
Cotton,  description  of,  227 

relation  to  body,  227 
Cotton  plant,  227 
Crop  rotation,  reasons  for,  305 
Crowding,  menace  to  health,  30 
Culex,  135 
Culture  medium,  67 
Current,  electric,  348 

sources  of,  351 
Currents,  convection,  185,  190,  191,  192 

direction  of  air,  65 

electric  wire  resistance,  363 

Decay,  119,  165 

cause  of,  119 

of  teeth,  165 
Diaphragm,  60 

D  ets,  differences  in,  reasons  for,  104 
Digestion,  99,  100 
Digestive  tract,  100 

nature  of,  101 
Diseases,  body  defenses  against,  163 

of  air  passages,  70 
Disinfectants,  use  of,  162 
Drainage  system,  relation  to  water  sup- 
ply, 79 

pipes,  151 

relation  to  home,  28,  50 
Drinking  cup,  hygienic,  167 
Drugs,  abuse  of,  171 

use  of,  170 
Dust,  danger  of,  66 

proper  removal  of,  68 


INDEX 


411 


Ear,  377 

Edison,  Thomas,  32,  33 

Electric  measuring  instruments 

ammeter,  364 

voltmeter,  364 

wattmeter,  368 
Electric  units 

ampere,  364 

kilowatt  hour,  368 

volt,  364 

watt-hour,  369 
Electricity,  circuit,  366 

control  of,  246 

electric  bell,  349 

electric  cells,  properties  of,  361  * 

electric  currents,  348,  360,  364 

electric  heating  devices,  354 

electric  iron,  356 

electric  toaster,  356 

electrical  toys,  387 

electromagnets,  345,  349 

in  the  home,  345,  360 

measuring  of,  364,  368 

pressure  of,  363 

production  of,  362 

relation  to  lighting,  246 

resistance  to,  362 

static,  386 
Electromagnet,  description  of,  345 

how  to  make,  349 
Elytra,  323 
Emulsion,  234 
Energy,  52,  338 

electricity  and  heat,  355 

from  food,  94 

sun  source  of,  52 
Environment,  40 

scoring  of,  55 

Enzymes,  relation  to  digestion,  102 
Exercise,  33,  34 

Expiration,  relation  to  breathing,  62 
Extinguisher,  fire,  213,  215 
Extinguishing,  burning  fat,  214 

gasoline,  214 
Eyes,  adaptation,  260,  264 

care  of,  264 

change  in  the  pupil,  259 

control  of,  260 

defects  of,  260 

importance  of,  31,  253 

section  of,  258 
strain,  26 


Eyes  —  Continued 
structure  of,  257 
testing  of,  262 

Fabric,     effect     of    chemical    reagents, 

231 

Fainting,  73 
Farsightedness,  261 
Fats,  94 

tests  for,  96 
Faucets,  leaky,  85 

types  of,  84 
Feet,  care  of,  224 
Fireless  cooker,  112 
Fire,  211 

chemical  extinguishers,  213,  215 

dangers  of,  206,  210 

extinguishing,  212 

flames  for  light,  209 

losses,  207 

prevention  of,  205 

regulation  of,  190 

smothering,  212 

sources  of,  208 
Fire-making,  183 
Flax,  228 
Fleas,  137 
Flush  tank,  150 

how  it  works,  151 
Fly,  house  (Diptera) 

extermination  of,  134 

life  cycle  of,  134 

relation  to  home,  132 

trap,  135 
Focusing,  259 
Food  chart,  dietary,  106 
Foods,  53 

affected  by  bacteria,  120 

animal  origin,  98 

bulky  foods,  164 

carbon  and  water  in,  93 

classification  of,  no 

economy  of,  105 

flavors  of,  127 

indigestible,  164 

plant  origin,  97 

preparation  of,  99 

preservation  of,  121 

relation  to  health,  99,  165 

simple  foods,  164 

spoiling  of,  116 
Footpound,  339 


412 


INDEX 


Force,  333,  335 

centrifugal,  392 

centripetal,  393 
Friction,  337 

rolling,  337 

sliding,  337 
Fuel,  burning  elements  of,  179 

economy  of,  177 

heating  value,  178 

kinds  of,  176,  202 

sources  of,  176 
Fulcrum,  334,  335 
Fungi,  317 

types  of  harmful,  317,  318,  320 
Fuses,  368 

Games,  383,  393 
Gardening,  cultivation,  301 

indoor,  292 

science  in,  298 

spraying,  327 

value  of  birds,  328 
Gas,  advantage  of  mantle,  245 

desirability  of,  245 

fishtail  flame,  245 

flame,  luminous  and  non-luminous,  199 

in  the  home,  244 

meter,  201 

range,  199 

Gasoline,  treacherous  cause  of  fire,  211 
Germ  dangers,  158 
Germs,  see  Bacteria 

growth  of,  159 
Glass,  importance  of,  270 
Granite  quarry,  270 
Graph,  showing  temperature,  22 
Grasshoppers  (Orthoptera),  323 
Grease,  removal  of,  235 
Grounds,  planning  of,  286 
Gyroscope,  391,  392 

Hay  fever,  69 

Head,  related  to  insect,  319 

Health,  body  poisons,  166 

exercise  and,  167 

rest  and,  169 

rules  of,  34,  172 
Hearing,  376 
Heart,  145 
Heat,  51 

distributing,  185 

from  electricity,  247,  355 


Heat  —  Continued 

heat  travels,  186 

in  homes,  196 

loss  from  body,  221 

relation  to  energy,  52 

steam,  196 

sun,  source  of,  51 
Hemiptcra,  323 
Home,  270 

beginnings  of,  25 

choosing  27,  28,  274 

duties  of  children  at,  33,  168 

efficiency  in,  32 

electricity  in,  360 

environment  of,  55 

grounds  of,  287 

grounds  surrounding,  286 

heating  of,  189 

ideal,  27 

ideal  location  and  drainage,  28 

ideal  score  card,  36,  37 

motors  in,  352 

recreation  in,  33 

regulation  of  light  in,  241,  243 

removal  of  wastes,  146 

requirements,  27 

scoring  of,  35 

suburban,  25 

use  of  color  in,  277 

water  supply  in,  80 
Hot-air  furnace,  191,  192 

advantages     and     disadvantages 

193 

Hotbed,  use  of,  310 
Hot- water  heating  system,  194 

advantages     and     disadvantages 

iQS 

how  a  room  is  warmed,  194 

principle  of,  193 
Hot  water,  supply  of,  200 
House,  floors  of  a  well-planned,  275 
Humus,  50 
Hydrogen,  93 

burning,  180 

Iceless  refrigerator,  124 
Ichneumon  flies,  327 
Imago,  320 

relation  to  butterfly,  320 
Immunity,  163 

antitoxin  treatment,  163 
Impervious  layer,  77 


of 


of, 


INDEX 


413 


Infection,  161 

how  it  takes  place,  161 
Inoculation,  relation  to  soil,  317 
Insect,  318 

abdomen,  319 

classification  of,  140 

collecting,  322 

damage  to  clothing,  139 

description  of,  319 

friends,  327 

garden  friends,  328 

harmful  to  fruit  trees,  327 

household  pests,  138,  139 

how  to  fight,  138,  139,  325 

injurious,  329 

life  history  of,  321 

recognition  of,  322 
Inspiration,    in   relation    to    breathing, 

62 

Insulating  material,  360 
Intestines,  100 
Iris,  258 

Kerosene  emulsion,  326 

light,  244 

Kilowatt  hours,  369 
Kindling  temperature,  181 
Kitchen,  a  model,  126 

cleanliness  in,  127 

ideal,  280 

Labor-saving  devices,  332 

Lanz,  David,  140 

Larva,  320 

Laveran,  13 

Leaf,  food  manufactory,  308,  309 

Legumes,  304 

related  plants,  304 
Lenses,  254 

focal  lengths,  254 

use  in  focusing,  255 

uses  of,  256,  401 
Lever,  333,  335 

principle  of,  334 
Lice,  137 
Light,  51,  238 

artificial,  243 

home  use,  241 

necessity  for  life,  51 

relation  to  man,  239 

sources  of,  238 

sunlight,  242 


Light  —  Continued 

surfaces  diffusing,  241 

tungsten,  248 
Lighting,  artificial,  244 

candle,  244 

electricity,  247 

gas,  244 

illustration  of,  249 

kerosene,  244 

methods  of,  250 
Lime-sulphur  fungicide,  326 
Lime-sulphur  spray,  326 
Lime-paris  green,  326 
Linen,  description  of,  228 
Lists,    garden    vegetables,    insects,    and 

prevention  and  cure,  325 
Living  room,  ideal,  279 
Lungs,  capacity  of,  63,  64 

give  off  wastes,  63,  64 

relation  to  breathing,  60 

Machines,  in  the  home,  332 

law  of,  338 

mechanical  advantage,  335 

sewing,  340 

washing,  342 
Magnets,  electromagnets,  345,  349 

laws  of  magnetic  poles,  346 

magnetic  field,  347 

properties  of,  346,  348 
Magnetism,  law  of,  347 

magnetize  iron  bar,  348 
Malaria,  13 

Manganese  dioxide,  361 
Manson  and  Warren,  16 
Map  showing  tuberculosis  districts,  30 
Marketing,  108 
Matches,  209 

relation  to  fires,  183 
Mechanical  advantage,  335 
Mechanical  toys,  385 
Menu,  how  to  select,  108 

proper,  109 

Metamorphosis,  of  butterfly,  320 
Meter,  gas,  201 
Microscope,  394 

Mind,  influence  on  digestion,  104 
Molds,  fruiting  bodies,  119 

in  the  home,  118 

spores,  119 
Mosquitoes,  14,  135 

anopheles,  14,  135 


INDEX 


Mosquitoes  —  Continued 

life  history  of,  14,  15,  136 

relation  to  malaria,  14 

relation  to  yellow  fever,  137 
Moths,  life  history  of,  319 

relation  to  clothes,  139 
Musical  scale,  378 
Music  and  noise,  378 

Nearsightedness,  260 
Neutralization,  234 
Nitrates,  relation  to  soil,  305 

soluble,  315 
Nitrogen,  43,  93 

cycle  of,  316 

related  to  soil,  304 
Nodules,  304 

related  to  plants,  305 
Noise,  378 
Nutrients,  classification  of,  94 

function  of,  94 

test  for,  95,  96 

Oil  fields,  177 
Opaque,  240 
Oxidation,  47 

relation  to  oxygen,  46 
Oxygen,  93,  145 

relation  to  air,  42 

Pasteur,  Louis,  126 
Pasteurization,  126 

pasteurizing  apparatus,  125 
Peristalsis,  103 
Pests,  329 

damage  done  by,  131 

life  history  of  the  fly,  133 

relation  to  home,  141,  142,  143 
Phonograph,  380 
Photography,  396 
Picture,  enlarging,  401 

making,  400 

printing  of,  400 
Pinhole  camera,  397 
Plant  enemies,  327 
Planting,  293 

city  gardening,  293 

crop  rotation,  305 

for  pleasure,  293 

for  profit,  293 

relation  to  soil,  303 

seed  table  for  home  gardening,  311 


Plants,  changed  into  living  material,  306 

friends,  328,  329 

pests,  314,  317 

relation  to  soil,  303,  305 

root-hairs,  304 

starch-making  power,  306 

test  for  food,  305 
Plate  culture,  67 
Pneumatic  tank  system,  82,  83 
Polyps,  70 

Preservatives,  in  relation  to  foods,  121 
Prism,  257 
Projects,  list  of,  20 
Prolegs,  relation  to  butterfly,  320 
Protein,  94 

food  rich  in,  95 
Pumps,  force,  82 

lift,  81 
Pupa,  320 
Pupil,  258 
Puzzles,  383 

Radiation,  185 
Rain  water,  76 
Rats,  140 

relation  to  man,  140 
Reading,  good,  381 
Recreation,  indoor,  372 

outdoor,  294,  391 

relation  to  home  life,  372 
Reflection,  240 
Refrigerator,  122 

construction  of,  123 

iceless,  124 

use  of,  123 

value  of,  122 

Resistance  in  wire  to  electricity,  363 
Respiration,  artificial,  71 

of  cells,  62 

organs  of,  69 

products  of,  63 

relations  to  activity,  62 
Retina,  258 
Rooms,  bedroom,  278 

dining  room,  279 

living  room,  279 
Ross,  14 

Sal  ammoniac,  361 
Sanitation,  bathroom,  148 

flush  tank,  148 

garbage  pails,  153 


INDEX 


415 


Sanitation  —  Continued 

plumbing,  147 

Save  life,  artificial  respiration,  71 
Science,  in  the  garden,  298 

method  of,  n 

recent  progress  in,  1 2 

relation  to  discovery  of  malaria,  13 

study  of,  1 6 

use  in  daily  life,  13,  17 

use  in  home  work,  18 

use  in  straight  thinking,  17 
Sclerotic,  258 
Semicircular  canals,  377 
Septic  tank,  153,  154 
Sewage,  disposal  of,  152 
Shears,  333 
Sheep,  226 
Short  circuit,  danger,  367 

description  of,  366 
Silk,  description  of,  229 

relation  to  heat,  230 
Siphon,  method  of  working,  149 
Skin,  220 

bathing  of,  222 

section  through,  220 
Smothering,  212 
Snakes,  330 
Soap,  use  of,  233 

washing  powders,  234 
Soil,  air  in,  301 

composition  of,  49,  299 

effect  of  cultivation,  301,  302 

formation  of  organic,  50 

harrowed  and  packed,  302 

inorganic,  302 

nitrogen  from,  304 

relation  to  home,  50 

relation  to  planting,  49 

water  in,  300 
Solution,  meaning  of,  86 

soluble,  86 
Sound,  373 

due  to  vibration,  373 
Spectrum,  258 
Speech,  375 
Speed,  change  of,  340 
Spiracles,  320 

Spontaneous  combustion,  211 
Spots  and  stains,  removal,  235 
Springs  and  wells,  77 

relation  to  underground  water,  77 

safe  and  deadly,  78 


Stamp  collecting,  384 
Stars,  402 

groups  of,  404 

Large  Dipper,  403 

North  Star,  403 

our  relation  to,  404 

shooting,  405 
Steam  heat,  195 

advantages  of,  197 

description  of,  196 

disadvantages  of,  197 

heat  stored  in  steam,  196 

protection  of  loss  of  heat,  197 
Stone,  270 

artificial,  271 

granite  quarry,  270 

life  of  building,  271 
Stoves,  coal,  description  of,  190 
Stringed  instruments,  379 
Sun,  position  of,  52 
Sunlight,  absorption  of,  242 

Teeth,  102,  165 

care  of,  165 

decay,  165 

uses  of,  102 
Telephone,  352 
Temperature,  181 

kindling,  181 

measurement  of,  22,  182 

regulation  of,  220 

relation  to  body,  183 
Tepee,  26 
Tests,  astigmatism,  262 

for  farsightedness,  262 

for  nearsightedness,  262 
Textile  fibers,  231 
Thermometer,  clinical,  182 

house,  182 
Thermos  bottle,  125 
Thorax,  319 

related  to  insect,  319 
Toxins,  163 
Tracheae,  323 
Transformer,  351 
Translucent,  240 
Transparent,  239 

transparency,  experiment,  240 
Traps,  152 
Trees,  arrangement  of,  288 

relation  to  home,  289 

use  of,  289 


416 


INDEX 


Tungsten  light,  248 
advantage  of,  248 

Underclothes,  223 
kinds,  222 
mesh,  223 
uses,  223 

Vaccination,  163 

Vacuum  sweeper  and  cleaner,  353 

system  of,  354 
Ventilation,  need  of,  65 

principles  involved,  66 

relation  to  health,  65 
Vermiform  appendix,  100 
Villi,  100 
Vitamines,  107 
Vitreous  humor,  258 
Vocal  cords,  375 
Voice,  375 

control,  376 
Volt,  364 
Voltage,  363 
Voltmeter,  364 

Wastes  or  poisons,  144,  145 
body  poisons,  166 
removal  from  body,  145 
removal  from  home,  146 

Water,  47 

composition  of,  75,  180 


Water  —  Continued 

cycle  of,  76 

hard,  86,  87 

impure,  78 

lifted  by  air  pressure,  80 

pure,  27,  74 

purification,  87 

rain,  76 

relation  to  body,  48 

relation  to  home,  79 

relation  to  soil,  300 

soft,  86,  87 
Water  seal,  151,  152 
Weighing,  336 
Weight,  333,  335 
Wells,  77 

artesian,  77 

deadly,  79 

pollution  of,  152 

safe,  79 
Windpipe,  60 
Wood,  cross  section  of,  268 

relation  of  markings,  270 
Wool,  description  of,  226 

relation  to  body,  227 
Work,  unit  of,  339 

Yeasts,  117 

used  in  bread  making,  117 

Zinc  rod,  361 


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